Engine Controls - Self-Diagnostics: Diagnosis Mazda MX-5 NB рестайлинг

SELF-DIAGNOSTIC SYSTEM

Note. For following, manufacturer recommends use of World Diagnostic System (WDS), New Generation Star (NGS) or equivalent scan tools.

Using World Diagnostic System (WDS) Scan Tool To Retrieve DTCs

Information not available from manufacturer. Recommend consulting instruction manual from scan tool manufacturer for specific instructions.

Using New Generation Star (NGS) Scan Tool To Retrieve DTCs

1. Apply parking brake. Place shift lever in Park (A/T) or Neutral (M/T). Block wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature.
2. Perform visual inspection. Ensure air cleaner and inlet ducts are clean, and system wiring harness is properly connected. Check for bent or broken connector terminals and corroded or loose wires. Check Powertrain Control Module (PCM), sensors and actuators for physical damage. Check engine coolant for proper level and mixture. Check for proper transmission fluid level and quality.
3. Turn ignition off. Ensure proper memory (EPROM) card is inserted into NGS scan tool. Connect service connections of adapter cable to vehicle DLC-2 and NGS scan tool. (Scheme 13) Connect NGS scan tool power supply cable to power and listen for a double beep to indicate that scan tool is on.
4. Start engine. If engine will not start, turn ignition on and program scan tool using the following steps: Select VEHICLE & ENGINE SELECTION. Select SELECT NEW VEHICLE YEAR & MODEL. Select DIAGNOSTIC DATA LINK. Select PCM-POWERTRAIN CONTROL MODULE. Select DIAGNOSTIC TEST MODE. Select READ/CLEAR DIAGNOSTIC TEST RESULTS. Select START and follow scan tool prompts.

Scheme 13

Using New Generation Star (NGS) Scan Tool To Retrieve Pending Codes

1. Apply parking brake. Place shift lever in Park (A/T) or Neutral (M/T). Block wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature.
2. Perform visual inspection. Ensure air cleaner and inlet ducts are clean, and system wiring harness is properly connected. Check for bent or broken connector terminals and corroded or loose wires. Check Powertrain Control Module (PCM), sensors and actuators for physical damage. Check engine coolant for proper level and mixture. Check for proper transmission fluid level and quality.
3. Turn ignition off. Ensure proper memory (EPROM) card is inserted into NGS scan tool. Connect service connections of adapter cable to vehicle DLC-2 and NGS scan tool. (Scheme 13) Connect NGS scan tool power supply cable to power and listen for a double beep to indicate that scan tool is on.
4. Start engine. If engine will not start, turn ignition on and program scan tool using the following steps: Select GENERIC OBD II FUNCTIONS. Select CONT. Select PENDING TROUBLE CODES. Select START and follow scan tool prompts. If scan tool reads NO DTCS AVAILABLE/NO RESPONSE, perform PID/DATA MONITOR in GENERIC OBD II FUNCTIONS and ensure that LINK COMMUNICATION ERROR, MODULE NOT RESPONDING or CHECK IGNITION STATUS AND CABLE CONNECTIONS message does not appear.

Using Generic Scan Tool

1. Apply parking brake. Place shift lever in Park (A/T) or Neutral (M/T). Block wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature.
2. Perform visual inspection. Ensure air cleaner and inlet ducts are clean, and system wiring harness is properly connected. Check for bent or broken connector terminals and corroded or loose wires. Check Powertrain Control Module (PCM), sensors and actuators for physical damage. Check engine coolant for proper level and mixture. Check for proper transmission fluid level and quality.
3. Ensure scan tool meets OBD-II standard. Follow scan tool manufacturer's operating instructions to connect equipment and record DTCs.

ON-BOARD SYSTEM READINESS TEST MODE

On-Board System Readiness (OSR) test mode indicates OBD-II system operating status by indicating status of each system monitor (complete or incomplete). There are 2 types of system monitors. Misfires, fuel system and comprehensive components are continuous monitoring-type functions and will be identified by a CONT message on the scan tool. Catalyst, EGR system, EVAP system and oxygen sensor are monitored during each drive cycle only. When the drive cycle sensor monitor is complete, a YES message will display.

Apply parking brake. Place shift lever in Park (A/T) or Neutral (M/T). Block wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature.

Perform visual inspection. Ensure air cleaner and inlet ducts are clean, and system wiring harness is properly connected. Check for bent or broken connector terminals and corroded or loose wires. Check Powertrain Control Module (PCM), sensors and actuators for physical damage. Check engine coolant for proper level and mixture. Check for proper transmission fluid level and quality.

Turn ignition off. Ensure proper memory (EPROM) card is inserted into NGS scan tool. Connect service connections of adapter cable to vehicle DLC-2 and NGS scan tool. (Scheme 13) Connect NGS scan tool power supply cable to power and listen for a double beep to indicate that scan tool is on.

To enter OSR test mode, program scan tool using the following steps

1. Select GENERIC OBD II FUNCTIONS.
2. Select TESTS.

If system status initialization is necessary, use following procedures

1. Press CANCEL key repeatedly to return to main menu.
2. Select GENERIC OBD II FUNCTIONS.
3. Select CONT.
4. Select CLEAR DIAGNOSTIC CODES.
5. Select START and follow scan tool prompts.

CLEARING DIAGNOSTIC TROUBLE CODES

Note. DO NOT disconnect vehicle battery to clear DTCs.

Using New Generation Star (NGS) Scan Tool

Press C-ALL button and press trigger.

Ensure scan tool meets OBD II standards. Follow scan tool manufacturer's operating instructions to connect equipment and clear DTCs.

TEST EQUIPMENT

All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated differently in testing procedure. When instructed to use a fused jumper wire, ensure fused jumper wire is equipped with an in-line 5-amp fuse.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Note. Vehicle with immobilizer system can be identified by a solid urethane ignition key head.

Note. Before performing any diagnostic test, refer to WARNINGS, CAUTIONS and NOTES under DIAGNOSTIC TESTS .

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TESTS

Note. Vehicle with immobilizer system can be identified by a solid urethane ignition key head.

Note. If Powertrain Control Module (PCM) replacement is instructed in following testing, always ensure PCM connectors and ground circuits are okay. If either are suspect, repair and repeat testing to confirm PCM malfunction.

Note. Before performing any diagnostic test, refer to WARNINGS, CAUTIONS and NOTES under SELF-DIAGNOSTIC SYSTEM for system functions and system diagnostic procedures.

Note. If more than one DTC is stored at PCM memory, always perform diagnosis from first DTC stored at PCM memory, unless stated otherwise in test procedure.

Note. If component testing procedure is not covered in DTC Self-Diagnosis article, for component testing, see SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.

Note. For identification of circuits, terminals and wire colors referenced in testing procedure, see appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.

Note. In some instances a short to ground or a short to power may cause damage to control modules. Do not replace control modules until testing proves these conditions do not exist. Also verify that ground circuits have good continuity to ground.

Note. Check connectors within a suspect circuit for loose connection, loose female terminals, terminals pushed out of their connectors, water or terminal corrosion.

Note. Self-diagnostic test procedures are for use with New Generation Star (NGS) scan tool. If a generic scan tool is used, ensure scan tool is certified to OBD-II standard.

Diagnostic Procedure

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 13.
2. Classify Intermittent Concern Or Continuous Concern - Leave ignition on. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If DTC P0010 is present again, go to next step. If DTCs are not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect OCV (Oil Control Valve) Connector For Poor Connection - Turn ignition off. Disconnect OCV harness connector. (Scheme 14) Check for poor connection due to damaged, pulled-out terminals, corrosion, etc. If connector and terminals are okay, go to next step. If connector and terminals are faulty, repair or replace as necessary. After repair, go to step 13.
4. Inspect OCV (Oil Control Valve) Electrical Malfunction - Measure resistance between OCV terminals "A" and "B". Resistance reading should be 6.9-7.9 ohms. If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace OCV. After repair, go to step 13.
5. Classify Malfunction At Power Supply Circuit Or Control Circuit - Turn ignition on, engine off. Measure voltage between ground and OCV harness connector terminal "A" (Yellow wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If voltage reading is not as specified, go to next step. If battery voltage is present, malfunction is at control circuit, go to step 9.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 14) Check for poor connection at terminal "4D" (Yellow wire) due to damaged, pulled-out terminals, corrosion, etc. If connector and terminals are okay, go to next step. If connector and terminals are faulty, repair or replace as necessary. After repair, go to step 13.
7. Inspect Power Circuit For Short To GND - Check for continuity between ground and OCV harness connector terminal "A" (Yellow wire). If no continuity is found, go to next step. If continuity is found, repair short circuit to ground in Yellow wire between OCV harness connector terminal "A" and PCM 31-pin harness connector terminal "4D". After repair, go to step 13.
8. Inspect Power Circuit For Open Circuit - Turn ignition off. Check for continuity between OCV harness connector terminal "A" and PCM harness connector terminal "4D" (Yellow wire). If continuity is found, go to next step. If continuity is not found, repair open circuit in Yellow wire between OCV harness connector terminal "A" and PCM 31-pin harness connector terminal "4D". After repair, go to step 13.
9. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. Check for poor connection at connector terminal "4R" (Violet/Yellow wire), due to damaged, pulled-out terminals, corrosion, etc. If connector and terminals are okay, go to next step. If connector and terminals are faulty, repair or replace as necessary. After repair, go to step 13.
10. Inspect Control Circuit For Short To Power - Turn ignition on, engine off. Check voltage between ground and OCV harness connector terminal "B" (Violet/Yellow wire). Voltage should not be present. If voltage is not present, go to next step. If voltage is present, repair short circuit to voltage in Violet/Yellow wire between OCV harness connector terminal "B" and PCM 31-pin harness connector terminal "4R". After repair, go to step 13.
11. Inspect Control Circuit For Short To GND - Turn ignition off. With OCV and PCM harness connectors disconnected, check for continuity between ground and OCV harness connector terminal "B". If continuity is not found, go to next step. If continuity is found, repair short circuit to ground in Violet/Yellow wire between OCV harness connector terminal "B" and PCM 31-pin harness connector terminal "4R". After repair, go to step 13.
12. Inspect Control Circuit For Open Circuit - Check for continuity in Violet/Yellow wire between OCV harness connector terminal "B" and PCM 31-pin harness connector terminal "4R". If continuity is present, go to next step. If continuity is not present, repair open circuit in Violet/Yellow wire between OCV harness connector terminal "B" and PCM 31-pin harness connector terminal "4R". After repair, go to next step.
13. Verify Troubleshooting Of DTC P0010 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0010 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
14. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 14

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5.
2. Inspect Oil Control Valve (OCV) For Malfunction - Start engine. Increase engine RPM. Stop engine and remove OCV. See «OIL CONTROL VALVE»(ref-151901-S16613050262003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Check position of spool valve in OCV. (Scheme 15) If spool valve is located at retard position, go to next step. If spool valve is not located at retard position, replace OCV. After repair, go to step 5.
3. Inspect Stopper Pin Mechanism - Remove timing belt. See appropriate article in ENGINES. Inspect stopper pin. See «VARIABLE VALVE TIMING ACTUATOR»(ref-151892-S12664811892003010900000) under VARIABLE VALVE TIMING SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If stopper pin mechanism is okay, go to next step. If stopper pin mechanism is faulty, replace variable valve timing actuator. After repair, go to step 5.
4. Inspect Rotor Position Remove variable valve timing actuator. See «VARIABLE VALVE TIMING ACTUATOR»(ref-151901-S38245530762003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. If rotor position is at maximum valve timing retard, valve timing mechanism is normal. Possible intermittent problem. Intermittent concern may be removed by cleaning mode of variable valve timing control function. Go to next step. If rotor position is not at maximum valve timing retard, replace variable valve timing actuator. After repair, go to next step.
5. Verify Troubleshooting Of DTC P0011 Completed Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0011 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
6. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 15

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Verify Related Pending Code Or Stored DTCs - Leave ignition on. Using scan tool, verify related pending DTC or other stored DTCs in PCM memory. If DTC P0010 is not present, go to next step. If DTC P0010 is present. Perform diagnostic procedure according to «DTC P0010: CAMSHAFT ACTUATOR CIRCUIT»(ref-151884-S05759046962003010900000).
3. Verify Engine Oil Pressure - Start engine. Check oil pressure warning light at instrument cluster. If warning light illuminates, perform engine oil pressure test. For engine oil pressure test, see appropriate article in ENGINES. If warning light does not illuminate, go to next step.
4. Verify Timing Belt Installation - Stop engine. Remove timing belt cover. Ensure camshaft and crankshaft timing marks are pointing to correct alignment mark. If timing belt is properly installed, go to next step. If timing belt is not properly installed, reinstall or replace timing belt as necessary. For timing belt removal and installation see appropriate article in ENGINES. After repair, go to step 7.
5. Inspect Oil Control Valve (OCV) For Malfunction - Remove variable valve timing actuator. See «VARIABLE VALVE TIMING ACTUATOR»(ref-151901-S38245530762003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Check position of spool valve in OCV. If spool valve is located at retard position, variable valve timing mechanism is normal. Problem is intermittent. Intermittent concern may be removed by cleaning mode of variable valve timing control function. Go to next step. If spool valve is not located at retard position, replace variable valve timing actuator. After repair, go to step 7.
6. Inspect Engine Oil Runner - Inspect engine oil runners for clogging or leakage at following points: Between OCV and variable valve timing actuator. Between oil pressure switch and OCV. In variable valve timing actuator. If any clogging or leakage is found, repair as necessary. After repair, go to next step. If clogging or leakage is not found, variable valve timing mechanism is normal. Problem is intermittent. Intermittent concern may be removed by cleaning mode of variable valve timing control function. Go to next step.
7. Verify Troubleshooting Of DTC P0012 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0012 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect HO2S (Front) Connector For Poor Connection - Turn ignition off. Disconnect front HO2S 4-pin harness connector. (Scheme 16) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
3. Inspect HO2S Heater (Front) - Measure resistance between front HO2S connector terminals "C" and "D". Resistance reading should be 5.0-6.8 ohms. If resistance reading is as specified, go to next step. If resistance reading is not a specified, replace front HO2S. After repair, go to step 8.
4. Inspect Power Circuit Of HO2S Heater (Front) For Open Circuit - Turn ignition on, engine off. Measure voltage between ground and HO2S 4-pin harness connector terminal "C" (Black/White wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open circuit in Black/White wire between front HO2S 4-pin harness connector terminal "C" and main fuse block (inside vehicle). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
5. Inspect PCM Connector Poor Connection - Turn ignition off. Disconnect PCM 24-pin harness connector. (Scheme 16) Check for poor connection at terminal "3J" (Black/Orange wire) due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
6. Inspect Control Circuit Of HO2S Heater (Front) For Short To GND - Check for continuity between ground and front HO2S 4-pin harness connector terminal "D" (Black/Orange wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Black/Orange wire between front HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3J". After repair, go to step 8.
7. Inspect Control Circuit Of HO2S Heater (Front) For Open Circuit - Check for continuity in Black/Orange wire between front HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3J". If continuity is found, go to next step. If continuity is not found, repair open circuit in Black/Orange wire between front HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3J". After repair, go to next step.
8. Verify Troubleshooting Of DTC P0031 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0031 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 16

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect HO2S (Front) Terminals - Turn ignition off. Disconnect front HO2S 4-pin harness connector. (Scheme 16) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
3. Inspect HO2S Heater (Front) - Measure resistance between front HO2S connector terminals "C" and "D". Resistance reading should be 5.0-6.8 ohms. If resistance reading is as specified, go to next step. If resistance reading is not a specified, replace front HO2S. After repair, go to step 6.
4. Inspect PCM Terminal - Disconnect PCM 24-pin harness connector. (Scheme 16) Check for poor connection at terminal "3J" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 6.
5. Inspect HO2S (Front) Heater Control Circuit For Short To Power Circuit - Turn ignition on, engine off. Measure voltage between ground and front HO2S 4-pin harness connector terminal "D" (Black/Orange wire). Voltage should not be present. If voltage is not present, go to next step. If voltage is present, repair short circuit to voltage in Black/Orange wire between front HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal 3J". After repair, go to next step.
6. Verify Troubleshooting Of DTC P0032 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0032 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect HO2S (Rear) Connector For Poor Connection - Turn ignition off. Disconnect rear HO2S 4-pin harness connector. (Scheme 17) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 8.
3. Inspect HO2S Heater (Rear) - Measure resistance between rear HO2S connector terminals "C" and "D". Resistance reading should be 14.1-18.9 ohms. If resistance reading is as specified, go to next step. If resistance reading is not a specified, replace rear HO2S. After repair, go to step 8.
4. Inspect HO2S Heater (Rear) Power Circuit For Open - Turn ignition on, engine off. Measure voltage between ground and rear HO2S 4-pin harness connector terminal "C" (Black/White wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Black/White wire between rear HO2S 4-pin harness connector terminal "C" and fuse block (inside vehicle). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
5. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 24-pin harness connector. (Scheme 17) Check for poor connection at terminal "3P" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 8.
6. Inspect HO2S Heater (Rear) Signal Circuit For Short To GND - Check for continuity between ground and rear HO2S 4-pin harness connector terminal "D" (White/Black wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in White/Black wire between rear HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3P". After repair, go to step 8.
7. Inspect HO2S Heater (Rear) Control Circuit For Open - Check for continuity between rear HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3P" (White/Black wire). If continuity is found, go to next step. If continuity is not found, repair open circuit in White/Black wire between rear HO2S and PCM. After repair, go to next step.
8. Verify Troubleshooting Of DTC P0037 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0037 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 17

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect HO2S (Rear) Terminal - Turn ignition off. Disconnect rear HO2S 4-pin harness connector. (Scheme 17) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
3. Inspect HO2S Heater (Rear) - Measure resistance between rear HO2S connector terminals "C" and "D". Resistance reading should be 14.1-18.9 ohms. If resistance reading is as specified, go to next step. If resistance reading is not a specified, replace rear HO2S. After repair, go to step 6.
4. Inspect PCM Terminal - Disconnect PCM 24-pin harness connector. (Scheme 17) Check for poor connection at PCM 24-pin harness connector terminal "3P" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
5. Inspect HO2S Heater (Rear) Control Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and HO2S 4-pin harness connector terminal "D" (White/Black wire). Voltage should not be present. If voltage is not present, go to next step. If voltage is present, repair short circuit to voltage in White/Black wire between rear HO2S 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3P". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
6. Verify Troubleshooting Of DTC P0038 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0038 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine. Using scan tool, access Engine Coolant Temperature (ECT), Mass Airflow (MAF), Throttle Position (TP) and RPM PIDs. Warm-up engine until ECT PID is more than 176°F (70°C). Verify TP PID is more than 50 percent. Read MAF PID while RPM PID is less than 2000 RPM. If MAF PID reading is more than 9.88 lb/min. (74.7 grams/sec), go to step 4. If MAF PID reading is less than as specified, go to next step.
3. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Stop engine and let it cool-down. Re-start engine. Using scan tool, access Engine Coolant Temperature (ECT), Mass Airflow (MAF), Throttle Position (TP) and RPM PIDs. Warm-up engine until ECT PID is more than 176°F (70°C). Verify TP PID is more than 50 percent. Read MAF PID while RPM PID is more than 500 RPM. If MAF PID reading is less than 0.70 lb/min. (5.3 grams/sec), go to next step. If MAF PID reading is more than specified, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
4. Check MAF Sensor Terminals For Electrical Corrosion - Stop engine and turn ignition off. Disconnect MAF sensor 3-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 6.
5. Inspect PCM Connector For Poor Connection - Disconnect PCM 31-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to next step.
6. Verify Troubleshooting Of DTC P0101 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and warm-up engine until ECT PID is more than 176°F (70°C). Verify TP PID is more than 50 percent and read MAF and RPM PIDs. MAF PID should indicate less than 9.88 lb/min. (74.7 grams/sec) while RPM PID is less than 2000 RPM. And MAF PID should indicate more than 0.70 lb/min. (5.3 grams/sec) while RPM PID is more than 500 RPM. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0101 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9.
2. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine. Using scan tool, access MAF PID. MAF PID should be on a vehicle equipped with automatic transmission 0.30-0.41 lb/min (2.2-3.2 grams/sec) and with manual transmission 0.31-0.41 lb/min (2.3-3.2 grams/sec). If MAF PID is not as specified, go to next step. If MAF PID is as specified, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect MAF Sensor Connector For Poor Connection - Turn ignition off. Disconnect MAF sensor 3-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 9.
4. Check Power Supply Circuit For Open - Turn ignition on, engine off. Measure voltage between ground and MAF sensor 3-pin harness connector terminal "C" (White/Red wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open circuit in White/Red wire between MAF sensor 3-pin harness terminal "C" and main relay. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
5. Inspect MAF Sensor GND Circuit For Open Circuit - Turn ignition off. Check for continuity between ground and MAF sensor 3-pin harness connector terminal "A" (Black/Blue wire). If continuity is found, go to next step. If continuity is not found, repair open circuit in Black/Blue wire between MAF sensor 3-pin harness connector terminal "A" and PCM 32-pin harness connector terminal "4A". After repair, go to step 9.
6. Inspect Poor Connection Of PCM Connector - Disconnect PCM 31-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 9.
7. Inspect MAF Sensor Signal Circuit For Open Circuit - Check for continuity between MAF sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4X" (Pink wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Pink wire between MAF sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4X". After repair, go to step 9.
8. Inspect MAF Sensor Signal Circuit For Short - Check for continuity between following circuits: Ground and MAF sensor 3-pin harness connector terminal "B" (Pink wire). MAF sensor 3-pin harness connector terminals "A" (Black/Blue wire) and "B" (Pink wire). If continuity is not found, replace MAF sensor and go to next step. If continuity is found, repair short to ground in Pink wire or short circuit between Pink and Black/Blue wires. Repair as necessary. After repair, go to next step.
9. Verify Troubleshooting Of DTC P0102 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access MAF PID. MAF PID should be on a vehicle equipped with automatic transmission 0.30-0.41 lb/min (2.2-3.2 grams/sec) and with manual transmission 0.31-0.41 lb/min (2.3-3.2 grams/sec). Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0102 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 18

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine. Using scan tool, access MAF PID. MAF PID should be on a vehicle equipped with automatic transmission 0.30-0.41 lb/min (2.2-3.2 grams/sec) and with manual transmission 0.31-0.41 lb/min (2.3-3.2 grams/sec). If MAF PID reading is not as specified, go to next step. If MAF PID reading is as specified, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect MAF Sensor Connector For Poor Connection - Turn ignition off. Disconnect MAF sensor 3-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
4. Inspect MAF Signal Circuit For Short To Power Circuit - Turn ignition on, engine off. Measure voltage between ground and MAF harness 3-pin harness connector terminal "B" (Pink wire). Voltage reading should be 0.1 volt. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair short circuit in Pink wire between MAF sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4X". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
5. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 18) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
6. Verify Troubleshooting Of DTC P0103 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access MAF PID. MAF PID should be on a vehicle equipped with automatic transmission 0.30-0.41 lb/min (2.2-3.2 grams/sec) and with manual transmission 0.31-0.41 lb/min (2.3-3.2 grams/sec). Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0103 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Identify Trigger DTC For Freeze Frame Data - Identify DTC recorded in monitored FREEZE FRAME DATA screen. If DTC P0106 appears in FREEZE FRAME DATA screen, go to next step. If different DTC than P0106 appears in FREEZE FRAME DATA screen, follow appropriate DTC diagnostic procedure.
3. Inspect Connection Of EGR Boost Sensing Related Vacuum Hoses - Turn ignition off. Inspect EGR boost sensing related vacuum hoses for loose, damage, improper connection and/or leakage as follows: From EGR boost sensor to EGR boost sensor solenoid. From EGR boost sensor solenoid to EGR pipe. If related vacuum hoses are okay, go to next step. If related vacuum hoses are faulty, replace or repair as necessary. After repair, go to step 7.
4. Inspect EGR Boost Sensor Solenoid Air Filter For Clogging - Inspect EGR boost sensor solenoid air filter for clogging. If EGR boost sensor solenoid air filter is okay, go to next step. If EGR boost sensor solenoid air filter is clogged, repair clogging as necessary. After repair, go to step 7.
5. Inspect EGR Boost Sensor Solenoid For Being Stuck Open Or Close - Inspect EGR boost sensor solenoid for being stuck open or close. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR boost sensor solenoid is okay, go to next step. If EGR boost sensor solenoid is faulty, replace EGR boost sensor solenoid. After repair, go to step 7.
6. Inspect EGR Boost Sensor - Inspect EGR boost sensor. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR boost sensor is okay, go to next step. If EGR boost sensor is faulty, replace EGR boost sensor. After repair, go to next step.
7. Verify Troubleshooting Of DTC P0106 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODES 1, 2 and 3. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. After performing drive modes, monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0106 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Check Signal Circuit Voltage When EGR Boost Sensor Connector Is Disconnected - Disconnect EGR boost sensor 3-pin harness connector. (Scheme 19) Turn ignition on, engine off. Measure voltage between ground and EGR boost sensor 3-pin harness connector terminal "B" (Pink wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. Voltage should be more than 4.8 volts. If voltage reading is as specified, go to next step. If voltage reading is not as specified, go to step 4. NOTE: If DTCs P0122 and P0452 are also present with P0107, see «REFERENCE VOLTAGE TEST»(ref-151884-S21606399602003010900000) Troubleshooting procedure. If no other DTC is present, go to next step.
3. Check Power Supply Circuit Voltage At EGR Boost Sensor Connector - Turn ignition on, engine off. Measure voltage between ground and EGR boost sensor 3-pin harness connector terminal "C" (Light Green/Red wire). Voltage reading should be 4.5-5.5 volts. If voltage reading is as specified, check for poor connection at EGR boost sensor 3-pin harness connector terminal "C" (Light Green/Red wire). If connector is faulty, repair or replace as necessary. After repair, go to step 6. If connector is okay, replace EGR boost sensor. After repair, go to step 6. If voltage reading is not as specified, repair open or short circuit in Light Green/Red wire between EGR boost sensor 3-pin harness connector terminal "C" and PCM 31-pin harness connector terminal "4L". After repair, go to step 6.
4. Inspect EGR Boost Sensor Signal Circuit For Short To GND - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 19) Check continuity between ground and EGR boost sensor 3-pin harness connector terminal "B" (Blue/Yellow wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Blue/Yellow wire between EGR boost sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4AE". After repair, go to step 6.
5. Inspect EGR Boost Sensor Signal & GND Circuit For Short To Each Other - Check continuity between EGR boost sensor harness connector terminals "A" (Black/Red wire) and "B" (Blue/Yellow wire). If continuity is not found, go to next step. If continuity is found, repair short in circuits (Black/Red and Blue/Yellow wires) between EGR boost sensor 3-pin harness connector and PCM 31-pin harness connector. After repair, go to next step.
6. Verify Troubleshooting Of DTC P0107 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0107 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 19

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect Connection Of EGR Boost Sensor Connector - Turn ignition off. Verify EGR boost sensor 3-pin harness connector is securely connected. If proper connection is found, go to next step. If connector is not connected properly, reconnect and secure EGR boost sensor connector. After repair, go to step 8.
3. Inspect EGR Boost Sensor Connector For Poor Connection - Disconnect EGR boost sensor 3-pin harness connector. (Scheme 19) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
4. Inspect EGR Boost Sensor GND Circuit For Open Circuit - Check continuity between ground and EGR boost sensor 3-pin harness connector terminal "A" (Black/Red wire). If continuity is found, go to next step. If continuity is not found, repair open circuit in Black/Red wire between EGR boost sensor 3-pin harness connector and PCM 31-pin harness connector terminal "4O". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
5. Check PCM Connector - Disconnect PCM 31-pin harness connector. (Scheme 19) Check for poor connection at terminal "4O" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8
6. Inspect EGR Boost Sensor Signal Circuit For Short To Reference Voltage Circuit - Check for continuity between EGR boost sensor 3-pin harness connector terminals "B" (Blue/Yellow wire) and "C" (Light Green/Red wire). If continuity is not present, go to next step. If continuity is present, repair short between EGR boost sensor circuits (Blue/Yellow and Light Green/Red wires). After repair, go to step 8.
7. Inspect EGR Boost Sensor Signal Circuit For Open Circuit - Check for continuity in Blue/Yellow wire between EGR boost sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal " 4AE". If continuity is present, go to next step. If continuity is not present, repair open circuit in Blue/Yellow wire between EGR boost sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal " 4AE". After repair, go to next step.
8. Verify Troubleshooting Of DTC P0108 Completed - Return vehicle to original condition. Using NGS tester or equivalent, clear DTCs from PCM memory. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0108 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5.
2. Inspect IAT Sensor Connector For Poor Connection - Turn ignition off. Disconnect IAT sensor harness connector. (Scheme 20) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 5.
3. Inspect IAT Sensor - Measure resistance between IAT sensor connector terminals "A" and "B". Resistance reading should be 2210-2690 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace IAT sensor. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 5.
4. Inspect PCM Connector For Poor Connection - Disconnect PCM 31-pin harness connector. (Scheme 20) Check terminals "4N" and "4O" for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to next step.
5. Verify Troubleshooting Of DTC P0111 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0111 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
6. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 20

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect IAT Sensor Terminal - Turn ignition off. Disconnect IAT sensor harness connector. (Scheme 20) Check IAT sensor connector terminals for damaged, bent, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
3. Determine If IAT Sensor Malfunction Or Harness Malfunction - Measure resistance between IAT sensor connector terminals. Resistance reading should be 2200-2690 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace IAT sensor. After repair, go to step 6.
4. Inspect IAT Signal Circuit For Short To GND - Disconnect PCM 31-pin harness connector. (Scheme 20) Check for continuity between ground and IAT sensor harness connector terminal "B" (Pink/Blue wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground inPink/Blue wire between IAT sensor harness connector terminal "B" and PCM 31-pin harness connector terminal "4N". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
5. Inspect IAT Circuits For Short Each Other - Check for continuity between IAT sensor harness connector terminals "A" (Black/Red wire) and "B" (Pink/Blue wire). If continuity is not present, go to next step. If continuity is present, repair short between IAT sensor circuits (Black/Red and Pink/Blue wires). After repair, go to next step.
6. Verify Troubleshooting Of DTC P0112 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0112 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9.
2. Inspect IAT Sensor Connector For Poor Connection - Turn ignition off. Disconnect IAT sensor harness connector. (Scheme 20) Check IATsensor harness connector for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 9.
3. Inspect IAT Sensor - Measure resistance between IAT sensor connector terminals. Resistance reading should be 2210-2690 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace IAT sensor. After repair, go to step 9.
4. Inspect IAT Sensor Signal Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and IAT sensor connector terminal "B" (Pink/Blue wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to battery voltage Pink/Blue wire between IAT sensor harness connector terminal "B" and PCM 31-pin harness connector terminal "4N". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
5. Inspect IAT Sensor Ground Circuit For Short To Power - Ensure ignition is on, engine off. Measure voltage between ground and IAT sensor harness connector terminal "A" (Black/Red wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to battery voltage in Black/Red wire between IAT sensor harness connector terminal "A" and PCM 31-pin harness connector terminal "4O". After repair, go to step 9.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 20) Check PCMterminals "4N" and "4O" for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 9.
7. Inspect IAT Sensor Signal Circuit For Open - Check continuity between IAT sensor harness connector terminal "B" and PCM harness connector terminal "4N" (Pink/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Pink/Blue wire between IAT sensor harness connector terminal "B" and PCM 31-pin harness connector terminal "4N". After repair, go to step 9.
8. Inspect IAT Sensor GND Circuit For Open - Check continuity between IAT sensor harness connector terminal "A" and PCM harness connector terminal "4O" (Black/Red wire). If continuity is present, go to next step. If continuity is not found, repair open circuit in Black/Red wire between IAT sensor harness connector and PCM 31-pin harness connector terminal "4O". After repair, go to next step.
9. Verify Troubleshooting Of DTC P0113 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0113 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect ECT Sensor Connector For Poor Connection - Turn ignition off. Disconnect ECT sensor 3-pin harness connector. (Scheme 21) Check ECTsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 6.
3. Inspect ECT Sensor - Measure resistance between ECT sensor 3-pin connector terminals "A" and "B". Resistance reading should be 2270-2740 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, go to step 5.
4. Inspect PCM Connector For Poor Connection Disconnect PCM 31-pin harness connector. (Scheme 21) Check PCMterminals "4P" and "4O" for poor connection due to damage, pulled-out pins, corrosion, etc. Also check connector terminals for tightness using feeler tool. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
5. Compare ECT PID Value - Compare ECT sensor value, with another new ECT sensor as follows: Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Leave old ECT sensor installed in engine. Connect new sensor to ECT sensor to 3-pin harness connector. Turn ignition on and record new ECT sensor PID value (PID value-1). Turn ignition off. Replace suspect ECT sensor with new ECT sensor. Start engine. Allow engine to idle for 5 minutes and record ECT PID value (PID value-2). Difference between new ECT sensor PID values 1 and 2 should be more than 10.1°F (5.6°C). If temperature values are not as specified, go to next step. If temperature values are as specified, go to step 7.
6. Verify Troubleshooting Of DTC P0116 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Let engine cool down for 6 hours Start engine and let it idle for 5 minutes. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0116 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

Scheme 21

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect If ECT Sensor Terminal Is Bent - Turn ignition off. Disconnect ECT sensor 3-pin harness connector. (Scheme 21) Check ECTsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
3. Determine If ECT Sensor Malfunction Or Harness Malfunction - Measure resistance between ECT sensor 3-pin connector terminals "A" and "B". Resistance reading should be 2270-2740 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace ECT sensor. After repair, go to step 6.
4. Inspect ECT Signal Circuit For Short To GND - Disconnect PCM 31-pin harness connector. (Scheme 21) Check for continuity between ground and ECT sensor 3-pin harness connector terminal "A" (Red/Blue wire). If continuity is not present, go to next step. If continuity is found, repair short circuit to ground inRed/Blue wire between ECT sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4P". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
5. Inspect ECT Circuit For Short Harnesses - Check for continuity between ECT sensor 3-pin harness connector terminals "A" (Red/Blue wire) and "B" (Black/Red wire). If continuity is not present, go to next step. If continuity is present, repair short between ECT sensor circuits (Red/Blue and Black/Red wires). After repair, go to next step.
6. Verify Troubleshooting Of DTC P0117 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Let engine cool down for 6 hours. Start engine and let it idle for 5 minutes. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0117 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect ECT Sensor Connector For Poor Connection - Turn ignition off. Disconnect ECT sensor 3-pin harness connector. (Scheme 21) Check ECTsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 8.
3. Determine If ECT Sensor Malfunction Or Harness Malfunction - Measure resistance between ECT sensor 3-pin connector terminals "A" and "B". Resistance reading should be 2270-2740 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace ECT sensor. After repair, go to step 8.
4. Inspect ECT Sensor Signal Circuit For Short To Power - Measure voltage between ground and ECT sensor 3-pin harness connector terminal "A" (Red/Blue wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Red/Blue wire between ECT sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4P". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
5. Inspect PCM Connector For Poor Connection - Disconnect PCM 31-pin harness connector. (Scheme 21) Check PCM31-pin harness connector for poor connection at terminals "4P" and "4O" due to damaged, pulled-out pins, corrosion, etc. Also check connector terminals for tightness using feeler tool. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
6. Inspect ECT Sensor Signal Circuit For Open Circuit - Check for continuity between ECT sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4P" (Red/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open circuit inRed/Blue wire between ECT sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4P". After repair, go to step 8.
7. Inspect ECT Sensor GND Circuit For Open Circuit - Check for continuity between ECT sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4O" (Black/Red wire). If continuity is present, go to next step. If continuity is not present, repair open circuit inBlack/Red wire between ECT sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4O". After repair, go to next step.
8. Verify Troubleshooting Of DTC P0118 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0118 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Pending Code Or Stored DTC - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Retrieve pending and stored DTCs. If DTC P0101 is not retrieved, go to next step. If DTC P0101 is also retrieved. See «DTC P0101: MASS AIRFLOW SENSOR CIRCUIT RANGE PERFORMANCE MALFUNCTION»(ref-151884-S06682980812003010900000) diagnostic procedure.
2. Verify Related Repair Information Availability - Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0121. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 10.
3. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine. Using scan tool, access ECT, TP and MAF PIDs. Warm-up engine until ECT PID is more than 158°F (70°C). Drive vehicle and read TP PID while MAF PID is more than 8.36 lbs/min (63.2 grams/sec). If TP PID is more than 12.5 percent, go to next step. If TP PID is not more than 12.5 percent, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
4. Verify TP PID - Leave engine running. Using scan tool, clear DTCs from PCM memory and access TP, MAF and RPM PIDs. Read TP PID while MAF PID is below 5.3 lbs/Min (0.7 grams/sec) and RPM PID is above 500 RPM. If TP PID is above 50 percent, go to step 6. If TP PID is not above 50 percent, go to next step.
5. Verify Current INPUT Signal Status - Is Concern Intermittent Or Constant - Drive vehicle and read MAF PID. MAF PID should change according to driving conditions. If MAF PID change as specified, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article. If MAF PID does not change as specified, check MAF sensor and circuits. See «MASS AIRFLOW SENSOR»(ref-134969-S23927342962002022100000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.
6. Check TP Sensor Terminals For Electrical Corrosion - Turn ignition off. Disconnect TP sensor 3-pin harness connector. (Scheme 22) Check TPsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 10.
7. Check GND Circuit For Voltage Drop - Measure resistance between ground and TP sensor 3-pin harness connector terminal "B" (Black/Red wire). Resistance reading should be about zero ohms. If resistance reading is as specified, go to next step. If resistance reading is not as specified, repair open or short circuit (in Black/Red wire) between TP sensor 3-pin harness connector terminal "B" and PCM 31-pin harness connector terminal "4O". For circuits identification, see appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
8. Verify TP Sensor - While operating throttle valve slowly from idle position to full open position, measure resistance between TP sensor 3-pin connector terminals "A" and "B". Resistance reading should change smoothly in proportion with throttle valve opening angle. If resistance reading changes as specified, go to next step. If resistance reading does not change as specified, replace TP sensor. After repair, go to step 10.
9. Check PCM Terminals For Electrical Corrosion - Disconnect PCM 31-pin harness connector. (Scheme 22) Check PCMfor poor connection at terminals "4L", "4V" and "4O", due to damaged, pulled-out pins, corrosion, etc. Also check connector terminals for tightness using feeler tool. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to next step.
10. Verify Troubleshooting Of DTC P0121 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access RPM, ECT, TP and MAF PIDs. Verify TP PID reading is less than 50 percent while MAF PID reading is less than 0.66 lb/min (5 grams/sec) and RPM PID reading is more than 500 RPM. Let engine idle until ECT PID reading is more than 158°F (70°C). Drive vehicle and read TP and MAF PIDs. TP PID reading should be more than 12.5 percent for more than 5 seconds. MAF PID reading should be 8.36 lbs/min (63.2 grams/sec). Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0121 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure.

Scheme 22

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Check TP Sensor Circuit For Open Circuit - Turn ignition off. Disconnect TP sensor 3-pin harness connector. (Scheme 22) Check continuity between TP sensor connector terminals "A" and "C". If continuity is present, check for poor connection at TP sensor terminal "C", repair or replace as necessary. After repair, go to next step. If continuity is not present, replace TP sensor. After repair, go to step 6. NOTE: Before proceeding with next step, check retrieved DTCs. If DTCs P0107 and P0452 are also present with P0122, see «REFERENCE VOLTAGE TEST»(ref-151884-S21606399602003010900000) Troubleshooting procedure.
3. Check Power Supply Circuit Voltage At TP Sensor Connector - Turn ignition on, engine off. Measure voltage between ground and TP sensor 3-pin harness connector terminal "A" (Light Green/Red wire). Voltage reading should be 4.5-5.5 volts. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short circuit in Light Green/Red wire between TP sensor 3-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4L". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
4. Verify TP Signal Circuit For Open - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 22) Check continuity between TP sensor 3-pin harness connector terminal "C" and PCM 31-pin harness connector terminal "4V" (Green /Black wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Green /Black wire between TP sensor 3-pin harness connector and PCM 31-pin harness connector terminal "4V". After repair, go to step 6.
5. Verify TP Signal Circuit For Short To GND - Check continuity between ground and PCM 31-pin harness connector terminal "4V" (Green/Black wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Green /Black wire between TP sensor 3-pin harness connector terminal "C" and PCM 31-pin harness connector terminal "4V". After repair, go to next step.
6. Verify Troubleshooting Of DTC P0122 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Depress and release accelerator pedal several times. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0122 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Check TP Sensor Connector - Turn ignition off. Verify TP sensor harness connector is properly and securely connected. If connector is okay, go to next step. If connector is faulty, reconnect TP sensor connector tight and secure. After repair, go to step 8.
3. Inspect TP Sensor Connector For Poor Connection - Turn ignition off. Disconnect TP sensor 3-pin harness connector. (Scheme 22) Check TPsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 8.
4. Check TP Sensor Resistance - Measure resistance between following TP sensor terminals: Terminals "A" and "B". Resistance reading should be 2500-5000 ohms. Terminals "B" and "C". Resistance reading should be 200-1100 ohms. If resistances readings are as specified, go to next step. If any resistance readings are not as specified, replace TP sensor. After repair, go to step 8.
5. Verify TP Sensor GND Circuit For Open At TP Sensor Connector - Check continuity between ground and TP sensor 3-pin harness connector terminal "B" (Black/Red wire). If continuity is not present, go to next step. If continuity is present, go to step 7.
6. Check PCM Connector - Disconnect PCM 31-pin harness connector. (Scheme 22) Check PCM harness connector terminal "4L", "4V" and "4O" for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8
7. Verify TP Signal Circuit For Short To Constant Voltage Circuit - Check continuity between TP sensor 3-pin harness connector terminals "A" (Light Green/Red wire) and "C" (Green/Black wire). If continuity is not present, go to next step. If continuity is present, repair short between TP sensor circuits (Light Green/Red and Green/Black wires). After repair, go to next step.
8. Verify Troubleshooting Of DTC P0123 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0123 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine and let idle until normal operating temperature is reached. Using scan tool, monitor ECT PID. If ECT PID reading is less than 140°F (60°C), go to next step. If ECT PID reading is more than 140°F (60°C), problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect ECT Sensor Connector For Poor Connection - Turn ignition off. Disconnect ECT sensor 3-pin harness connector. (Scheme 21) Check ECTsensor for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
4. Inspect ECT Sensor - Measure resistance between ECT sensor 3-pin connector terminals "A" and "B". Resistance reading should be 2270-2740 ohms at 68°F (20°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace ECT sensor. After repair, go to step 6.
5. Inspect PCM Connector For Poor Connection - Disconnect PCM 31-pin harness connector. (Scheme 21) Check PCM 31-pin harness connector terminals "4P" and "4O" for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to next step.
6. Verify Troubleshooting Of DTC P0125 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access ECT PID and wait until ECT PID is less than 68°F (20°C). Start engine and let idle until normal operating temperature is reached. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0125 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Also monitor for other DTCs. If other DTCs are set, follow appropriate DTC diagnostic procedure. Check service bulletins for repair information related to DTC P0126 or P0128. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Verify Coolant Thermostat Operation - Turn A/C system and any other electrical load off. Turn ignition off. Remove cooling fan relay located next to engine compartment main fuse block. Using scan tool, access ECT PID. Start engine and let it idle until ECT PID reads 210°F (99°C). Using a fused jumper wire, short cooling fan relay 4-pin harness connector terminals "A" (Black/White wire) and "B" (Red/Yellow wire). (Scheme 23) Monitor ECT PID. If ECT PID decreased continuously and stopped at 184-190°F (84-88°C), thermostat is okay. Go to step 4. If ECT PID is not as specified, go to next step.
3. Inspect Coolant Thermostat For Being Stuck Open - Stop engine. Allow engine to cool down. Remove thermostat and inspect for being stuck open. If thermostat is okay, inspect ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-151892-S08510237282003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. Replace ECT sensor if necessary. After repair, go to next step. If thermostat is found stuck open, replace thermostat. After repair, go to next step. NOTE: During next procedure, if workshop interior/exterior temperature difference is significant, PCM might not operate thermostat monitor. Therefore, it is recommended to cool down engine outside of workshop.
4. Verify Monitoring Condition For Repair Verification - Return vehicle to original condition and allow engine to cool down. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access ECT and IAT PID, make sure that each value is within following conditions: IAT is more than 14°F (-10°C). Difference between ECT and IAT is less than 10.8°F (6°C). If any PID is out of specification, take corrective action (e.g. cool down engine), repeat this step. If there are no PIDs out of specification: DTC P0126, go to next step. DTC P0128, go to step 6. NOTE: This test procedure requires actual driving. Chassis roller cannot be used on this test. Therefore, it is recommended to cool down engine outside of workshop. During test drive, constant speed should be maintained, although 2 or 3 stops is acceptable during every 5 minutes of driving time (e.g. traffic signals). Stop-and-go (e.g. case of traffic congestion) is not acceptable during test period. Test period depends on ECT at engine start. (e.g. If ECT is 14°F (-10°C), monitoring period is 38 minutes and if ECT is 86°F (30°C), monitoring period is 8 minutes. Therefore it is recommended to cool down engine outside workshop).
5. Verify Troubleshooting Of DTC P0126 Completed - Start engine. Turn A/C system and any other electrical load off. Using scan tool, access DIAGNOSIS MONITORING TEST RESULTS function and monitor TEST No. 10:32:00. Drive vehicle from 25-62 MPH until test value is changed. Verify TEST No. 10:30:00 value. If value is not more than minimum value, go to next step. If value is less than minimum value, repair terminal as necessary. After repair, go to step 7.
6. Verify Troubleshooting Of DTC P0128 Completed - Return vehicle to original condition. Cool down engine. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access ECT PID and make sure ECT PID is 20-95°F (-7-35°C). Start engine and let it idle until ECT PID reaches more than 160°F (71°C). Drive vehicle 6 MPH or more. Access DIAGNOSIS MONITORING TEST RESULTS function. Verify TEST No. 10:31:00 values. If value is less than maximum value, go to next step. If value is more than maximum value, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 23

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0131. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 17.
2. Verify Related Pending Code & Stored DTCs - Turn ignition on, engine off. Retrieve pending and stored DTCs. If no other DTC is present, go to next step. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If malfunction code recordedis P0131, go to next step. If malfunction code recordedis different than P0131, follow appropriate DTC diagnostic procedure.
4. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine and let idle until normal operating temperature is reached. Using scan tool, access O2S11 PID. Verify O2S11 PID while racing engine (in PARK) and make sure that each value is within following conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PID readings are as specified, go to next step. If any O2S11 PID reading is not as specified, replace front H2OS. After repair, go to step 17. NOTE: Purge solenoid valve may also be referred to as a purge control solenoid valve.
5. Inspect Purge Solenoid Valve Operation - Turn ignition off. Inspect purge solenoid valve operation. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is operating properly, go to step 10. If purge solenoid valve is not operating properly, replace purge solenoid valve. After repair, go to step 17.
6. Inspect PCV Valve Operation - Inspect PCV valve operation. See «POSITIVE CRANKCASE VENTILATION»(ref-151892-S37528392572003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PCV valve is operating properly, go to next step. If PCV valve is not operating properly, replace PCV valve. After repair, go to step 17.
7. Inspect Fuel Line Pressure (Low Fuel Line Pressure) - Turn ignition off. Release fuel pressure from fuel system. Install fuel pressure gauge. Turn ignition on, engine off. For proper fuel pressure test. See «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel pressure is not as specified, go to next step. If fuel pressure is as specified, go to step 10.
8. Inspect Fuel Line From Fuel Pump To Fuel Delivery Pipe - Turn ignition off. Visually inspect fuel lines for leaks. If fuel leak is found, repair or replace component as necessary and go to step 17. If fuel leak is not found, inspect fuel filter for following condition: Restriction or clogging at fuel filter (high pressure). If restriction or clogging is found, replace fuel filter (high pressure). Foreign material or stain in fuel filter (low pressure). If foreign material or stain is found inside fuel filter, clean fuel tank and fuel filter (low pressure). After repair, go to step 17. If all fuel filters are okay, go to next step.
9. Inspect Fuel Pump Maximum Pressure - Turn ignition on. Perform fuel pump maximum pressure test. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pump maximum pressure should be less 92 psi (640 kPa). If fuel pump maximum pressure is less than 92 psi (640 kPa), replace fuel pressure regulator. After repair, go to step 17. If fuel pressure is not as specified, check fuel pump circuit for open or poor connection. Repair as necessary. If fuel pump circuit is okay, replace fuel pump. After repair, go to step 17.
10. Check Ignition Coil Operation & High-Tension Lead With Timing Light - Return vehicle to original condition. Start engine and let it idle. Using a timing light, verify blinking condition on each cylinder. If any cylinders show faulty blinking condition, go to next step. If all cylinders show good blinking condition, go to step 14.
11. Check High-Tension Leads Of No Blinking Cylinder - Turn ignition off. Inspect high-tension leads for installation, condition, corrosion on terminal, open lead or damaged cover. If high-tension leads are okay, go to next step. If any high-tension lead is faulty, replace high-tension lead. After repair, go to step 17.
12. Inspect Power Supply Terminal At Ignition Coil Connector - Disconnect ignition coils 3-pin harness connector. (Scheme 24) Turn ignition on, engine off. Measure voltage between ground and ignition coil harness connectors terminal "A" (Black/White wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short in Black/White wire between suspected ignition coil 3-pin harness connector terminal "A" and ignition switch terminal "IG1". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 17.
13. Inspect Ignition Coil Resistance - Check ignition coil resistance. «IGNITION SYSTEM»(ref-151892-S29131808752003010900000) in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If coil resistance is okay, go to next step. If coil resistance is not okay, replace faulty ignition coil. After repair, go to step 17.
14. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. For proper engine compression test. See «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to next step.
15. Inspect Fuel Injector Operation - Turn ignition off. Inspect fuel injector operation. See «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If fuel injectors are operating properly, go to next step. If any fuel injector is faulty, replace fuel injector(s). After repair, go to step 17. WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
16. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary and go to next step.
17. Verify Troubleshooting Of DTC P0131 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access ECT PID. Let engine idle until ECT PID is more than 158°F (70°C). Increase and keep engine speed to more than 1500 RPM for at least one minute. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0131 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
18. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 24

1. Verify Related Repair Information Availability - Turn ignition on. Retrieve pending and stored DTCs. If any other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). Also monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0132. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 11.
2. Verify Related Pending Code & Stored DTCs - Turn ignition off, then start engine. Connect scan tool to DLC-2. (Scheme 13) Verify pending code and stored DTCs. If no other DTCs are present with P0132, go to next step. If other DTCs are present, go to appropriate DTC Troubleshooting procedure for those DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If DTC P0132is recorded, go to next step. If recordedDTC is different than P0132, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
4. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Start engine and let idle until normal operating temperature is reached. Using scan tool, access O2S11 PID. Verify O2S11 PID while racing engine (in park) and ensure that each value is within following specification/conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PID readings are as specified, go to next step. If any O2S11 PID reading is not as specified, replace front H2OS. After repair, go to step 11.
5. Inspect Fuel Line Pressure (Excessive Fuel Line Pressure) - Turn ignition off. Perform fuel pressure test. Release fuel pressure from fuel system. Install fuel pressure gauge. For proper fuel pressure test, see «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel pressure is not as specified, go to next step. If fuel pressure is as specified, go to step 11.
6. Verify Vacuum Is Leading To Pressure Regulator - Start engine and let it idle. Disconnect vacuum hose from fuel pressure regulator. Verify that vacuum is felt at opening port of disconnected vacuum hose. If vacuum is felt, proceed as follow: Perform fuel pump maximum pressure test. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Inspect fuel return pipe for clogging, repair or replace if necessary. If both tests are okay, replace fuel pressure regulator. After repair, go to step 11. If no vacuum is felt at disconnected vacuum hose, verify vacuum hoses are connected correctly and proceed as follow: If vacuum hoses are properly connected, replace pressure regulator control solenoid valve. If vacuum hoses are not properly connected, reconnect vacuum hoses to correct position. After repair, go to step 11. NOTE: Purge solenoid valve may also be referred to as a purge control solenoid valve.
7. Inspect Purge Solenoid Valve Operation - Turn ignition off. Inspect purge solenoid valve operation. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is operating properly, go to step 9. If purge solenoid valve is not operating properly, replace purge solenoid valve. After repair, go to step 11.
8. Inspect PCV Valve Operation - Inspect PCV valve operation. See «POSITIVE CRANKCASE VENTILATION»(ref-151892-S37528392572003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PCV valve is operating properly, go to next step. If PCV valve is not operating properly, replace PCV valve. After repair, go to step 11.
9. Inspect Fuel Injector Operation - Turn ignition off. Inspect fuel injectors operation. See «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If fuel injectors are operating properly, go to next step. If any fuel injector is faulty, replace fuel injector and go to step 11. WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
10. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary and go to next step.
11. Verify Troubleshooting Of DTC P0132 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access ECT PID. Let engine idle until ECT PID is more than 158°F (70°C). Increase and maintain engine speed to more than 1500 RPM for at least one minute. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0132 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
12. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0133. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify Related Pending Code & Stored DTCs - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Start engine. Retrieve pending and stored DTCs. If no other DTCs are present with P0133, go to next step. If DTC P0442, P0443, P0455, P0031, P0032 or P1450 with P0133 are present, follow appropriate DTC Troubleshooting. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). After repair, go to step 14.
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If DTC is P0133, go to next step. If DTCis different than P0133, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
4. Verify Current Input Signal Status - Start engine and let idle until normal operating temperature is reached. Using scan tool, access O2S11 PID. Verify O2S11 PID while racing engine (in park). Ensure that each value is within following conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PID readings are as specified, go to step 7. If any O2S11 PID reading is not as specified, go to next step.
5. Inspect Installation Of Front HO2S - Turn ignition off. Inspect front HO2S for proper installation. If sensor is tight, go to next step. If sensor is loose, resecure front HO2S. After repair, go to step 14.
6. Inspect Gas Leakage From Exhaust System - Check for exhaust leakage between exhaust manifold and front HO2S. If exhaust leak is found, repair or replace exhaust components as necessary. After repair, go to step 14. If exhaust leak is not found, replace front HO2S. After repair, go to step 14.
7. Inspect Long Term Fuel Trim - Turn ignition on. Using scan tool, access LONGFT1 PID. Compare LONGFT1 PID value with FREEZE FRAME DATA (FFD) recorded at step 1). If LONGFT1 PID value is less than FFD value, engine is driven under rich condition. Go to next step. If LONGFT1 PID value is more than FFD value, engine is driven under lean condition. Go to step 10.
8. Inspect Fuel Line Pressure (Excessive Fuel Line Pressure) - Start engine. Inspect fuel line fuel pressure. Release fuel pressure from fuel system. Install fuel pressure gauge. For proper fuel line pressure test. See «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel pressure is as specified, go to step 13. If fuel pressure is not as specified, go to next step.
9. Verify Vacuum Is Led To Pressure Regulator - Return vehicle to original condition.Start engine and let idle. Disconnect vacuum hose from fuel pressure regulator. If vacuum is felt at open port of disconnected vacuum hose, inspect fuel pump maximum pressure and fuel return pipe for restriction. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If any problem is present, replace suspect parts. If no problem is present, replace fuel pressure regulator. If no vacuum is felt at open port of disconnected vacuum hose, verify vacuum hoses are connected correctly. If vacuum hoses are okay, replace pressure regulator control solenoid valve. If vacuum hoses are not properly connected, reconnect vacuum hoses to correct position. Repair as necessary. After repair, go to step 14.
10. Inspect Fuel Line Pressure (Low Fuel Line Pressure) - Start engine. Inspect fuel line pressure with engine running. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel pressure is as specified, go to step 13. If fuel pressure is not as specified, go to next step.
11. Inspect Fuel Line From Fuel Pump To Fuel Delivery Pipe - Turn ignition off. Visually inspect fuel lines for leakage. If fuel leakage is found, repair or replace component as necessary. After repair, go to step 14. If fuel leak is not found, inspect fuel filters for following: Restriction or clogging at fuel filter (high pressure). If restriction or clogging is found. Replace fuel filter. After repair, go to step 14. Foreign material or stain in fuel filter (low pressure). If foreign material or stain is found inside fuel filter. Clean fuel tank and fuel filter. After repair, go to step 14. If both fuel filters are okay, go to next step.
12. Inspect Fuel Pump Maximum Pressure - Perform fuel pump maximum pressure test. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel pump maximum pressure is less than 92 psi (637 kPa), replace fuel pressure regulator. If fuel pressure is not as specified, inspect fuel pump circuit for open or poor connection. Repair or replace suspect circuit. If fuel pump circuit is okay, replace fuel pump. After repair, go to step 14. WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
13. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary and go to next step.
14. Verify Troubleshooting Of DTC P0133 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run OBD-II DRIVE MODE 1 and 3. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Stop vehicle and access ON BOARD READINESS TEST to inspect DRIVE MODE completion status. Verify Readiness Function Check (RFC) flag changes to YES for HO2S. If RFC flag does not change to YES, run DRIVE MODE again. Access MONITORING TEST RESULTS and verify following test values: 10:01:11, 10:02:11 or 10:03:11. If all test results are less than MAX value, go to next step. If all test results are not less than MAX value, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
15. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0134. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify Related Pending Code & Stored DTCs - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Start engine. Retrieve pending and stored DTCs. If no other DTC is present except P0131 and P0132, go to next step. If other DTC is present except P0131 and P0132, follow appropriate DTC Troubleshooting. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). After repair, go to step 14.
3. Identify Trigger DTC For Freeze Frame Data - Identify DTC that triggered freeze frame data. If DTC P0134 is on freeze frame data, go to next step. If any DTC other than DTC P0134 is on freeze frame data, go to Troubleshooting procedure for DTC that is on freeze frame data. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
4. Verify Current Input Signal Status - Start engine and let idle until normal operating temperature is reached. Using scan, access O2S11 PID. Verify O2S11 PID while racing engine (in park). Ensure that each value is within following conditions: More than 0.55 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.55 volt just after release of accelerator pedal (lean condition). If O2S11 PID readings are as specified, go to next step. If any O2S11 PID reading is not as specified, replace front HO2S. After repair, go to step 9.
5. Inspect Installation Of HO2S (Front) - Turn ignition off. Inspect front HO2S for proper installation. If no problem is found, go to next step. If problem is found, resecure front HO2S as necessary. After repair, go to step 9.
6. Inspect Gas Leakage From Exhaust System - Visually check if any exhaust leakage is found between exhaust manifold and front or rear HO2S. If any exhaust leakage is present, repair or replace faulty exhaust system components. After repair, go to step 9. If no exhaust leakage is present, check for open or short to ground circuit between front HO2S 4-pin harness connector terminal "A" and PCM 32-pin harness connector terminal "4W" (Blue wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9. WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
7. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary. After repair, go to step 9.
8. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. See «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to next step.
9. Verify Troubleshooting Of DTC P0134 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access RPM and ECT PIDs. Let engine idle until ECT PID is more than 158°F (70°C). Increase and maintain engine speed to more than 1500 RPM for at least one minute. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0134 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition off, then on (engine off). Verify pending code or stored DTCs using scan tool. If no other DTCs are present, go to next step. If other related DTCs are present, perform appropriate diagnostic and repair procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If malfunction code recordedis P0138, go to next step. If malfunction code recordedis different that P0138, follow appropriate DTC diagnostic procedure.
4. Inspect HO2S (Rear) Signal Circuit For Short To Power Supply Circuit - Turn ignition off. Disconnect rear HO2S 4-pin harness connector. (Scheme 17) Turn ignition on. Measure voltage between ground and rear HO2S 4-pin harness connector terminal "A" (Red wire). If one volt or less is present, go to next step. If battery voltage is present, repair short circuit to battery voltage between rear HO2S wires (Red and Black/White wires). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
5. Verify Current Input Signal Status - Start engine. Using scan tool, access O2S12 PID. Read and record O2S12 PID while racing engine at least 10 times (in park). If PID reading stays at less than 0.45 volt, go to next step. If PID reading stays at more than 0.45 volt, replace rear HO2S. After repair, go to next step.
6. Verify Troubleshooting Of DTC P0138 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODE 1 and 2. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0138 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to DTC P0140. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Retrieve pending and stored DTCs. If other related DTCs are present except P0131 and P0132, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If malfunction code recordedis P0140, go to next step. If malfunction code recordedis different that P0140, follow appropriate DTC diagnostic procedure.
4. Verify Current Input Signal Status - Start engine. Using scan tool, access O2S12 PID. Read and record O2S12 PID while racing engine at least 10 times (in park). PID reading should be more than 0.55 volt at least once during engine racing. If PID reading is as specified, go to step 7. If PID reading is not as specified, go to next step.
5. Inspect Installation Of HO2S (Rear) - Turn ignition off. Inspect rear HO2S for proper installation. Also check for exhaust leakage between exhaust manifold and rear HO2S. If no problem is found, go to next step. If problem is found, reinstall and secure rear HO2S and/or repair exhaust leak as necessary. After repair, go to step 9.
6. Inspect Gas Leakage From Exhaust System - Visually check if there is any gas/exhaust leakage between exhaust pipe and HO2S (rear). If any exhaust leakage is present, repair or replace faulty exhaust components as necessary. After repair, go to step 9. If exhaust leakage is not present, check wire harness for open or short to ground circuit between rear HO2S 4-pin harness connector terminal "A" and PCM 31-pin harness connector terminal "4AA (Red wire). WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
7. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary. After repair, go to step 9.
8. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. See «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to next step.
9. Verify Troubleshooting Of DTC P0140 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access ECT PID. Let engine idle until ECT PID is more than 158°F (70°C). Increase and maintain engine speed to more than 1500 RPM for at least one minute. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0140 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 18.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition on, engine off. Monitor for DTC or pending coderelated to this DTC. If no other DTC is set and no driveability concern is present, go to next step. If misfire DTC is present, go to step 7. If other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). If no other DTC is set, but driveability concern is present, go to step 7.
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If malfunction code recordedis P0171, go to next step. If malfunction code recordedis different than P0171, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
4. Verify Current Input Signal Status (Ignition Key To On/Idle) - Start engine and let idle until normal operating temperature is reached. Using scan tool, access ECT, MAF, TP, and VSS PIDs. For system PID specifications. See «SYSTEM INPUT SIGNAL SPECIFICATIONS»(ref-151884-S33304944652003010900000) table. SYSTEM INPUT SIGNAL SPECIFICATIONS Application Sensor Voltage At Idle Speed ECT 68°F (20°C) About 3.0 Volts 176°F (80°C) About 0.9 Volt MAF Switch on 0.9-2.0 Volts At idle-After Warm Up 1.7-2.4 Volts TP Close Throttle 0.1-1.1 Volts Wide Open Throttle 3.0-4.6 Volts VSS Voltage Should Moves Slightly Under 5.0 Volts While Driving If all systems input voltages are as specified, go to next step. If any system input voltage is not as specified, inspect suspect sensor and system wiring harness for excessive resistance. Repair or replace as necessary. appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 18.
5. Verify Current Input Signal Status Under Trouble Condition - Inspect same PIDs while simulating recorded FREEZE FRAME DATA conditions, If no input signal is drastically changed, go to next step. If any input signal is drastically changed, inspect suspect sensor and related wiring harnesses, repair or replace as necessary. After repair, go to step 18. NOTE: During next procedure, engine speed may change when rust penetrating agent is sprayed on air suction area. CAUTION: DO NOT spray rust penetrating agent on or near coils or plug wires, an arcing wire or coil could start a fire. Allow enough time for rust penetrating agent to dissipate.
6. Verify Current Input Signal Status Of HO2S (Front) - With engine running at idle and at normal operation temperature. Using scan tool, access O2S11 PID. Check O2S11 PID while engine is idling (in park) under following conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PIDs readings are okay, go to next step. If any O2S11 PID reading is not okay, inspect for air leaks due to cracks, damages and loose parts between following: From air cleaner to throttle body. From throttle body to dynamic chamber. From dynamic chamber to intake manifold. Vacuum hoses. If air suction (vacuum leak) is not found, go to next step. If air suction (vacuum leak) is found, repair or replace faulty component. After repair, go to step 18.
7. Inspect MAF V PID - Start engine. Using scan tool, access MAF PID. While racing engine RPM, verify MAF PID reading changes quickly according to engine RPM. If MAF PID reading changes as specified, go to next step. If MAF PID reading does not change as specified, replace MAF sensor. After repair, go to step 18.
8. Inspect For Excessive Air Suction Of Intake-Air System - Visually inspect intake-air system for loose, cracked or damaged hoses. If any malfunction is present, repair or replace source of air leak. After repair, go to step 18. If no malfunction is present, go to next step.
9. Inspect Fuel Line Pressure - Turn ignition off and perform fuel pressure test. Release fuel pressure from fuel system. Install fuel pressure gauge. For proper fuel pressure test. See «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel pressure is as specified, go to step 12. If fuel pressure is not as specified, proceed as follows: If fuel pressure is excessively high, check fuel pump maximum pressure and fuel return line for clogging. If any problem is found, repair or replace suspect parts. If no problem is found, replace fuel pressure regulator. After repair, go to step 18. If fuel pressure is low, go to next step.
10. Inspect Fuel Pump Maximum Pressure - Turn ignition on. Perform fuel pump maximum pressure test. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel pump maximum pressure is less than 92 psi (640 kPa), go to next step. If fuel pump pressure is not as specified, inspect fuel pump circuit for open or poor connection. Repair suspect circuit as necessary. After repair, go to step 18. If circuit is okay, replace fuel pump. After repair, go to step 18.
11. Inspect Fuel Line From Fuel Pump To Fuel Delivery Pipe - Turn ignition off. Visually inspect fuel lines for any leaks. If any fuel leak is found, repair or replace component as necessary. After repair, go to step 18. If fuel leak is not found, inspect fuel filters for following conditions: Restriction or clogging at fuel filter (high pressure). If restriction or clogging is found. Replace fuel filter. After repair, go to step 18. Foreign material or stain inside fuel filter (low pressure). If foreign material or stain is found inside fuel filter. Clean fuel tank and fuel filter. After repair, go to step 18. If both fuel filters are okay, replace fuel pressure regulator. After repair, go to step 18.
12. Check Ignition Coil Operation & High-Tension Lead With Timing Light - Return vehicle to original condition. Start engine and let it idle. Using a timing light, verify blinking condition on each cylinder. If all cylinders show blinking condition, go to step 16. If any cylinder shows a faulty blinking condition, go to next step.
13. Check High-Tension Leads Of No Blinking Cylinder - Turn ignition off. Inspect high-tension leads for installation, condition, corrosion on terminal, open lead or damaged cover. If high-tension leads are okay, go to next step. If any high-tension lead is faulty, replace high-tension lead. After repair, go to step 18.
14. Inspect Power Supply Terminal At Ignition Coil Connector - Disconnect ignition coil 3-pin harness connector. (Scheme 24) Turn ignition on. Measure voltage between ground and ignition coil 3-pin harness connector terminal "A" (Black/White wire). Battery voltage should be present. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short in Black/White wire between suspect ignition coil 3-pin harness connector terminal "A" and ignition switch terminal "IG1". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 18.
15. Inspect Ignition Coil Resistance - Check ignition coil primary and secondary resistances. See «IGNITION CHECKS»(ref-151876-S25784050672003010800000) in BASIC DIAGNOSTIC PROCEDURES article. If resistance readings are as specified, go to next step. If resistance readings are not as specified, replace faulty ignition coil. After repair, go to step 18.
16. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. For proper engine compression test, see «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to step 18.
17. Inspect Fuel Injector Operation - Turn ignition off. Remove fuel injector and inspect operation. See «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If fuel injectors are operating properly, go to next step. If any fuel injector is faulty, replace fuel injector. After repair, go to next step.
18. Verify Troubleshooting Of DTC P0171 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODES 1, 2 and 3. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0171 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
19. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition on, engine off. Monitor for DTC or pending coderelated to this DTC. If other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). If no other DTC is set, but driveability concern or rough idle is present, go to step 8. If no other DTC is set and no driveability concern or rough idle is present, go to next step.
3. Identify Trigger DTC For Freeze Frame Data - Check for triggered DTC on recorded FREEZE FRAME DATA. If malfunction code recordedis P0172, go to next step. If malfunction code recordedis different that P0172, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
4. Verify Current Input Signal Status (Ignition Key To On/Idle) - Start engine and let it idle until it reaches normal operating temperature. Using scan tool, access ECT, MAF, TP, and VSS PIDs. For system PID specifications, see «SYSTEM INPUT SIGNAL SPECIFICATIONS»(ref-151884-S33304944652003010900000) table. If all system input voltages are as specified, go to next step. If any system input voltage is not as specified, inspect suspect sensor and system wiring harness for excessive resistance. Repair or replace as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
5. Verify Current Input Signal Status Under Trouble Condition - Inspect same PIDs while simulating recorded FREEZE FRAME DATA conditions, If no input signal is drastically changed, go to next step. If any input signal is drastically changed, inspect suspected sensor and related wiring harness for excessive resistance. Repair or replace as necessary. After repair, go to step 9.
6. Verify Current Input Signal Status Of Front HO2S - With engine running at idle and at normal operating temperature. Using scan tool, access O2S11 PID. Verify O2S11 PID while racing engine (in park). Ensure that each value is within following conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PIDs readings are as specified, go to next step. If any O2S11 PID reading is not as specified, replace front HO2S. After repair, go to step 9.
7. Inspect Fuel Line Pressure - Turn ignition off and perform fuel pressure test. Release fuel pressure from fuel system. Install fuel pressure gauge. For proper fuel pressure test, see «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel line pressure should be 53-61 psi (370-420 kPa). If fuel pressure is as specified, go to next step. If fuel line pressure is not as specified, inspect fuel pump maximum pressure and fuel return line for clogging. If any problem is found, repair or replace suspected parts. If fuel pump and fuel return line are okay, replace fuel pressure regulator. After repair, go to step 9. NOTE: Purge solenoid valve may also be referred to as a purge control solenoid valve.
8. Inspect Purge Solenoid Valve For Stuck Open - Turn ignition off. Disconnect both vacuum hoses from purge solenoid valve. Blow air through purge solenoid valve vacuum hose fitting. If air does not flow through valve, go to next step. If air flows through valve, replace purge solenoid valve. After repair, go to next step.
9. Verify Troubleshooting Of DTC P0172 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODES 1, 2 and 3. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0172 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 21.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition on, engine off. Monitor for other DTC or pending coderelated to this DTC. If no other DTC is present, go to next step. If other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Verify Current Input Signal Status (Ignition Key At On/Idle) - Start engine and let it idle until normal operating temperature is reached. Using scan tool, access ECT, MAF, TP and VSS PIDs. For system PID specifications. See «SYSTEM INPUT SIGNAL SPECIFICATIONS»(ref-151884-S33304944652003010900000) table. If all system input voltages are as specified, go to next step. If any system input voltage is not as specified, inspect suspect sensor and system wiring harness, repair or replace as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 21.
4. Verify Current Input Signal Status Under Trouble Condition - Inspect same PIDs while simulating recorded FREEZE FRAME DATA conditions. If no input signal drastically changed, go to next step. If any input signal drastically changed, inspect suspect sensor and system wiring harness, repair or replace as necessary and go to step 21.
5. Inspect CMP Sensor - Turn ignition off. Perform CMP sensor inspection. See «CAMSHAFT POSITION SENSOR»(ref-151892-S16315825052003010900000) under ENGINE SENSOR & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CMP sensor is okay, go to next step. If CMP sensor is faulty, inspect for installation condition and damage to timing belt or gears, if problem is found repair or replace as necessary. If no problem is found, replace CMP sensor. After repair, go to step 21.
6. Verify CKP Sensor Installation Condition - Verify CKP sensor installation and condition (looseness or damage). If CKP sensor is properly installed and condition is okay, go to next step. If CKP sensor is found loose or damaged, secure or replace CKP sensor. See «CRANKSHAFT POSITION SENSOR»(ref-151901-S06665823822003010900000) under ENGINE SENSOR & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to step 21.
7. Check Ignition Coil Operation & High-Tension Lead With Timing Light - Return vehicle to original condition. Start engine and let it idle. Using a timing light, verify blinking condition on each cylinder. If all cylinder show good blinking conditions, go to step 21. If any cylinder show faulty blinking conditions, go to next step.
8. Check High-Tension Leads Of No Blinking Cylinder - Turn ignition off. Inspect high-tension leads for installation, condition, corrosion on terminal, open lead or damaged cover. If high-tension leads are okay, go to next step. If any high-tension leads is faulty, replace high-tension lead and go to step 21.
9. Inspect Power Supply Terminal At Ignition Coil Connector - Disconnect ignition coils 3-pin harness connectors. (Scheme 24) Turn ignition on. Measure voltage between ground and ignition coils harness connectors terminal "A" (Black/White wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short in Black/White wire between suspect ignition coil 3-pin harness connector terminal "A" and ignition switch terminal "IG1". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 21.
10. Inspect Ignition Coil Resistance - Leave ignition coils harness connectors disconnected and disconnect high tension led wires. Check ignition coils primary and secondary resistances. See «IGNITION CHECKS»(ref-151876-S25784050672003010800000) in BASIC DIAGNOSTIC PROCEDURES article. If resistance readings are as specified, go to next step. If any resistance reading is not as specified, replace faulty ignition coil. After repair, go to step 21.
11. Inspect MAF V PID - Return vehicle to original condition. Start engine and let it idle. Using scan tool, access MAF PID. While racing engine RPM, verify that MAF PID changes quickly according to engine RPM. If MAF PID changes as specified, go to next step. If MAF PID does not changes as specified, replace MAF sensor. After repair, go to step 21. NOTE: During next procedure, engine speed may change when rust penetrating agent is sprayed on air suction area. CAUTION: DO NOT spray rust penetrating agent on or near coils or plug wires, an arcing wire or coil could start a fire. Allow enough time for rust penetrating agent to dissipate.
12. Inspect Excessive Air Suction In Intake-Air System - Leave engine running at idle speed. While spraying rust penetrating agent in short spurts, inspect for air suction (vacuum leak) due to cracks, damages, or loose parts between following components: From MAF sensor to throttle body. From throttle body to dynamic chamber. From dynamic chamber to intake manifold. Vacuum hoses. If air suction (vacuum leak) is not found, go to next step. If air suction (vacuum leak) is found, repair or replace faulty component. After repair, go to step 21.
13. Inspect Fuel Line Pressure - Turn ignition off. Release fuel pressure from fuel system. Install fuel pressure gauge. For proper fuel pressure test. See «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 53-61 psi (370-420 kPa). If fuel line pressure is too low, go to next step. If fuel line pressure is as specified, go to step 16. If fuel line pressure is excessively high, check following: Fuel pump maximum pressure. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel return line for restriction. If any problem is present, repair as necessary. After repair, go to step 21. If no problem is present, replace fuel pressure regulator.
14. Inspect Fuel Pump Maximum Pressure - Perform fuel pump maximum pressure test. See «FUEL PUMP OPERATION»(ref-151876-S29945749962003013000000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pump maximum pressure should be 92 psi (640 kPa). If fuel pressure is less than 92 psi (640 kPa), go to next step. If fuel pump maximum pressure is not as specified, check fuel pump circuit for open or poor connection, repair or replace connector or circuit as necessary. After repair, go to step 21. If connector and circuits are okay, replace fuel pump. After repair, go to step 21.
15. Inspect Fuel Line From Fuel Pump To Fuel Delivery Pipe - Turn ignition off. Visually inspect fuel lines for leaks. If fuel leak is found, repair or replace component as necessary. After repair, go to step 21. If fuel leak is not found, inspect fuel filters for following condition: Restriction or clogging at fuel filter (high pressure). If restriction or clogging is found, replace fuel filter. Foreign material or stain in fuel filter (low pressure). If foreign material or stain is found inside low pressure fuel filter, clean fuel tank and fuel filter. If both fuel filters are okay, replace fuel pressure regulator. Repair fuel system as necessary. After repair, go to step 21.
16. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. For proper engine compression test, see «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to step 21. NOTE: Purge solenoid valve may also be referred to as a purge control solenoid valve.
17. Inspect Operation Of Purge Solenoid Valve - Turn ignition off. Inspect purge solenoid valve operation. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is operating properly, go to next step. If purge solenoid valve is not operating properly, replace purge solenoid valve. After repair, go to step 21.
18. Inspect PCV Valve Operation - Inspect PCV valve operation. See «POSITIVE CRANKCASE VENTILATION»(ref-151892-S37528392572003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PCV valve is operating properly, go to next step. If PCV valve is not operating properly, replace PCV valve. After repair, go to step 21.
19. Inspect Operation Of EGR Valve - Remove Exhaust Gas Recirculation (EGR) valve for inspection. Visually inspect valve for stuck open condition. If EGR valve is operating properly, go to next step. If EGR valve is not operating properly (stuck open), replace EGR valve. After repair, go to next step. WARNING: Removing radiator cap when radiator is hot is dangerous. Scalding coolant and steam may shoot out and cause serious injury. When removing radiator cap, wrap a thick cloth around and turn it slowly. NOTE: Large bubbles are normal since they are remaining air coming out from engine coolant passage.
20. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary. After repair, go to next step.
21. Verify Troubleshooting Of Misfire DTC P0300 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODE 1. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0300 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
22. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 12.
2. Verify Related Pending Code Or Stored DTCs - Monitor for DTC or pending coderelated to this DTC. If no other DTC is present, go to next step. If other DTC is present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Verify Current Input Signal Status (Ignition Key To On /Idle) - Start engine and let idle until normal operating temperature is reached. Using scan tool, access ECT, MAF, TP, RPM and VSS PIDs. For system PID specifications. See «SYSTEM INPUT SIGNAL SPECIFICATIONS»(ref-151884-S33304944652003010900000) table. If all system input voltages are as specified, go to next step. If any system input voltage is not as specified, inspect suspect sensor and system wiring harness, repair or replace as necessary. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 12.
4. Verify Current Input Signal Status Under Trouble Condition - Inspect same PIDs while simulating recorded FREEZE FRAME DATA conditions. If no input signal drastically changed, go to next step. If any input signal drastically changed, inspect suspect sensor and system wiring harness, repair or replace as necessary. After repair, go to step 12.
5. Inspect Spark Plug Condition - Turn ignition off. Remove spark plug from suspected cylinder. Check spark plug condition. If spark plug is okay, go to next step. If spark is cracked, has excessive wear, improper gap, replace spark plug. After repair, go to step 12. If spark plug is wet, fuel flooding is suspected. Go to step 10.
6. Verify High-Tension Lead Condition - Remove high-tension leads and check for cracks and spark shorts to cylinder head through high-tension lead insulator. If high-tension leads are okay, go to next step. If any high-tension leads is faulty, replace suspected high-tension lead. After repair, go to step 12.
7. Inspect Intake-Air System For Air Suction - Start engine and let it run at idle. While spraying rust penetrating agent in short spurts, inspect for air suction (vacuum leak) due to cracks, damaged, or loose parts between following components: From throttle body to dynamic chamber. From dynamic chamber to intake manifold. From intake manifold to cylinder heads. If air suction (vacuum leak) is not found, go to next step. If air suction (vacuum leak) is found, repair or replace suspect component. After repair, go to step 12.
8. Inspect Fuel Injector Harness - Turn ignition off. Disconnect fuel injector harness connector from suspected cylinder. Connect test light (LED) to fuel injector harness connector terminals. While cranking engine, check dim of test light. If test light illuminates as specified, go to next step. If test light does not illuminate as specified, check fuel injector harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. Repair or replace as necessary. After repair, go to step 12.
9. Inspect Sealing Of Engine Coolant Passage - Ensure to let engine cool down before performing this test. Check cooling system for combustion gasses. Remove radiator cap. Bleed air from cooling system. Start engine and let idle. Check for small bubbles which make coolant white at filler neck. If combustion gasses are not present, go to next step. If combustion gasses are present, repair leak as necessary. After repair, go to step 12. If sealing of engine coolant passage is okay, go to next step.
10. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. For proper engine compression test, see «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to step 12.
11. Inspect Fuel Injector Operation - Turn ignition off. Inspect fuel injectors operation. See «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If fuel injectors are operating properly, go to next step. If any fuel injector is faulty, replace fuel injector. After repair, go to next step.
12. Verify Troubleshooting Of Misfire DTC P0301, P0302, P0303 OR P0304 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and run DRIVE MODE 1. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0301, P0302, P0303 or P0304 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
13. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5.
2. Check Knock Signal Circuit For Short To Body GND - Turn ignition off. Disconnect KS harness connector. (Scheme 25) Turn ignition on. Measure voltage between ground and KS harness connector terminal "A" (White wire). Voltage reading should be about 5 volts. If voltage reading is as specified, go to step 4. If voltage reading is not as specified, repair open or short circuit in White wire between KS harness connector terminal "A" and PCM 31-pin harness connector terminal "4M". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 5.
3. Check PCM Connector - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 25) Check for poor connection at terminal due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 5.
4. Check Knock Sensor - Measure resistance between KS body and KS terminal "A". Resistance reading should be approximately 560,000. If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace KS. After repair, go to next step.
5. Verify Troubleshooting Of DTC P0327 Completed - Return vehicle to original condition. Let vehicle cool down for 6 hours. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let it idle for 5 minutes.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0327 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
6. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 25

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5.
2. Check Knock Signal Circuit For Open Circuit - Turn ignition off. Disconnect KS harness connector. (Scheme 25) Turn ignition on, engine off. Measure voltage between ground and KS harness connector terminal "A" (White wire). Voltage reading should be about 5 volts. If voltage reading is as specified, go to step 4. If voltage reading is not as specified, repair open or short circuit in White wire between KS harness connector terminal "A" and PCM 31-pin harness connector terminal "4M". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 5.
3. Check PCM Connector - Turn ignition off. Leave KS harness connector disconnected and disconnect PCM 31-pin harness connector. (Scheme 25) Check for poor connection at terminal due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 5.
4. Check Knock Sensor - Measure resistance between KS body and KS terminal "A". Resistance should be approximately 560,000 ohms. If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace KS. After repair, go to next step.
5. Verify Troubleshooting Of DTC P0328 Completed - Return vehicle to original condition. Let vehicle cool down for 6 hours. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let it idle for 5 minutes.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0328 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
6. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 10.
2. Determine If Intermittent Concern Or Continuous Concern - Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If DTC P0335 is present again, go to next step. If DTC P0335 is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect Poor Connection Of CKP Sensor Connector - Turn ignition off. Disconnect CKP sensor 3-pin harness connector. (Scheme 26) Check for poor connection at terminal due to damage, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 10.
4. Inspect Power Supply Circuit At CKP Sensor Connector - Turn ignition on, engine off. Measure voltage between ground and CKP sensor 3-pin harness connector terminal "A" (White/Red wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short circuit in White/Red wire between CKP sensor 3-pin harness connector terminal "A" and main relay 4-pin harness connector terminal "D". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
5. Inspect CKP Sensor Signal Circuit For Open Circuit - Disconnect PCM 24-pin harness connector. (Scheme 26) Check continuity between CKP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3Y" (Violet/White wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Violet/White wire between CKP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3Y". After repair, go to step 10.
6. Inspect CKP Sensor Signal Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and CKP sensor 3-pin harness connector terminal "B" (Violet/White wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Violet/White wire between CKP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3Y". After repair, go to step 10.
7. Inspect CKP Sensor Signal Circuit For Short To GND - Turn ignition off. Check continuity between ground and CKP sensor 3-pin harness connector terminal "B" (Violet/White wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Violet/White wire between CKP sensor 3-pin harness connector and PCM 24-pin harness connector. After repair, go to step 10.
8. Inspect CKP Sensor GND Circuit For Open Circuit - Check continuity between ground and CKP sensor 3-pin harness connector terminal "C" (Black/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/Blue wire between ground and CKP sensor 3-pin harness connector terminal "C". After repair, go to step 10.
9. Inspect CKP Sensor - Return vehicle to original condition. While cranking engine, backprobe and measure voltage between ground and PCM 24-pin harness connector terminal "3Y" (Violet/White wire). If voltage signal is found, go to next step. If voltage signal is not found, check crankshaft pulley for damage. Repair or replace crankshaft pulley as necessary. After repair, go to next step.
10. Verify Troubleshooting Of DTC P0335 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0335 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 26

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 11.
2. Classify Intermittent Concern Or Continuous Concern - Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let it idle until normal operating temperature is reached. Monitor for DTCs. If DTC P0340 is present again, go to next step. If DTC P0340 is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect Poor Connection Of CMP Sensor Connector - Turn ignition off. Disconnect CMP sensor 3-pin harness connector. (Scheme 27) Check for poor connection at terminal due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 11.
4. Inspect Power Supply Circuit At CMP Sensor - Turn ignition on, engine off. Measure voltage between ground and CMP sensor 3-pin harness connector terminal "A" (White/Red wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short circuit in White/Red wire between CMP sensor 3-pin harness connector terminal "A" and main relay 4-pin harness connector terminal "D". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 11.
5. Inspect CMP Sensor Signal Circuit For Open - Disconnect PCM 24-pin harness connector. (Scheme 27) Check continuity between CMP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3V" (Gray/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray/Blue wire between CMP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3V". After repair, go to step 10.
6. Inspect CMP Sensor Signal Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and CMP sensor 3-pin harness connector terminal "B" (Gray/Blue wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Gray/Blue wire between CMP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3V". After repair, go to step 11.
7. Inspect CMP Sensor Signal Circuit For Short To GND - Turn ignition off. Check continuity between ground and CKP sensor 3-pin harness connector terminal "B" (Gray/Blue wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Gray/Blue wire between CMP sensor 3-pin harness connector terminal "B" and PCM 24-pin harness connector terminal "3V". After repair, go to step 11.
8. Inspect CMP Sensor GND Circuit For Open - Check continuity between ground and CMP sensor 3-pin harness connector terminal "C" (Black/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/Blue wire between ground and CMP sensor 3-pin harness connector. After repair, go to step 11.
9. Inspect CMP Sensor - Return vehicle to original condition. While cranking engine, backprobe and measure voltage between ground and PCM 24-pin harness connector terminal "3V" (Gray/Blue wire). If any voltage signal is present, go to next step. If any voltage signal is not present, check camshaft pulley for damage. Replace camshaft pulley if necessary. After repair, go to next step.
10. Inspect CKP Sensor - Turn ignition off. Perform CKP sensor inspection. Check CKP sensor for following: CKP sensor is dirty. Crankshaft pulley is damaged. DTC P0335 is displayed, etc. If no problem is found, go to next step. If problem is found, repair or replace malfunctioning parts. After repair, go to next step.
11. Verify Troubleshooting Of DTC P0340 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and access MAF PID. MAF PID should be more than 0.36 lb/min. (2.7 grams/sec). Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0340 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
12. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 27

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect For Other DTCs - Leave ignition on. Monitor for other DTCs. If malfunction code recordedis P0401, go to next step. If malfunction code recordedis different than P0401, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Inspect Vacuum Hose Condition - Turn ignition off. Inspect EGR system vacuum hoses for clogs, damage, freezing, or vacuum leaks. If all vacuum hoses are okay, go to next step. If any vacuum hose is faulty repair or replace as necessary. After repair, go to step 8.
4. Inspect EGR Valve Malfunction - Perform EGR valve inspection. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR valve is okay, go to next step. If EGR valve is faulty, replace EGR valve. After repair, go to step 8.
5. Inspect EGR Boost Sensor Malfunction - Perform EGR boost sensor inspection. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR boost sensor is okay, go to next step. If EGR boost sensor is faulty, replace EGR boost sensor. After repair, go to step 8.
6. Inspect EGR Boost Sensor Solenoid Valve - Perform EGR boost sensor solenoid valve inspection. See «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR boost solenoid valve is okay, go to next step. If EGR boost solenoid valve is faulty, replace EGR boost sensor solenoid valve. After repair, go to step 8.
7. Inspect EGR Valve Passage - Turn ignition off. Remove EGR valve, inspect valve passage for clog, blockage and proper gasket installation. If EGR valve passage is okay and gasket is properly installed, go to next step. If EGR valve passage is plugged or gasket is not install properly, repair or replace components as necessary. After repair, go to step 8.
8. Monitor EGR System By Drive Mode - Using scan tool, run MODE 1 and 2. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Check EGR System Monitor completion status using On Board Readiness Test function. If EGR system has been monitored, go to next step. If EGR system has not been monitored, repeat this procedure.
9. Verify Troubleshooting Of DTC P0401 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access DIAGNOSTIC MONITORING TEST RESULTS of generic OBD-II functions and verify TEST ID 10:41:00 value is within specification, if value is within specification, monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0401 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 5.
2. Inspect For Other DTCs - Leave ignition on. Monitor for other DTCs. If malfunction code recordedis P0402, go to next step. If malfunction code recordedis different than P0402, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Inspect EGR Valve Gasket - Turn ignition off. Remove EGR valve, inspect EGR valve gasket for condition and proper installation. If EGR valve gasket is in good condition and properly installed, go to next step. If EGR valve gasket is faulty or not installed properly, repair or replace gasket as necessary. After repair, go to step 5.
4. Inspect EGR Valve Gasket Malfunction - Using scan tool, run MODE 1 and 2. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Check EGR System Monitor completion status using On-Board Readiness Test function. If EGR system has been monitored, go to next step. If EGR system has not been monitored, repeat this procedure.
5. Monitor EGR System By Drive Mode - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access DIAGNOSTIC MONITORING TEST RESULTS of generic OBD-II functions and verify TEST ID 10:41:00 value is within specification, if value is within specification, monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0402 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
6. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check for related Service bulletins and/or on-line repair information availability. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Classify Intermittent Concern Or Continuous Concern - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. If same DTC P0403 is present, go to next step. If same DTC P0403 is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect Poor Connection Of EGR Valve - Turn ignition off. Disconnect EGR valve 6-pin harness connector. Check for poor connection at terminal due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
4. Inspect Power Circuit For Open Circuit - Turn ignition on, engine off. Measure following EGR valve power circuit terminal voltage: EGR valve terminal "C" and body ground. EGR valve terminal "D" and body ground. If battery voltage is present, go to next step. If battery voltage is not present, repair or replace open circuit in White/Red wire in harness between EGR valve 6-pin harness connector terminals "C" and "D" and main relay 4-pin harness connector terminal "D". After repair, go to step 8.
5. Inspect EGR Valve - Measure resistance between following EGR valve terminals: Terminals "C" and "E". Terminals "C" and "A". Terminals "D" and "B". Terminals "D" and "F". If resistance readings are all about 22 ohms, go to next step. If any resistance reading is not about 22 ohms, replace EGR valve. After repair, go to step 8.
6. Inspect For Control Circuit For Short To Ground - Check continuity between following EGR valve control circuits: EGR valve terminal "E" and body ground. EGR valve terminal "A" and body ground. EGR valve terminal "B" and body ground. EGR valve terminal "F" and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in wire harness between EGR valve 6-pin harness connector and PCM 17-pin harness connector terminals. After repair, go to step 8.
7. Inspect Control Circuit For Open Circuit - Disconnect PCM 27-pin harness connector. Check continuity between following EGR valve control circuits. EGR valve terminal "E" and PCM terminal 2E. EGR valve terminal "A" and PCM terminal 2F. EGR valve terminal "B" and PCM terminal 2H. EGR valve terminal "F" and PCM terminal 2I. If continuity is present, go to next step. If continuity is not present, repair or replace wire harness for open circuit between EGR valve 6-pin harness connector and PCM 27-pin harness connector terminals. After repair, go to next step.
8. Verify Troubleshooting Of DTC P0403 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0403 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Verify Related Pending Code Or Stored DTCs - Stop engine and leave ignition on. Monitor for DTC or pending coderelated to this DTC. If no other DTC is present, go to next step. If other DTC related to this DTCis present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Inspect Exhaust System For Gas Leakage - Visually inspect exhaust system for gas leakage. If no exhaust gas leaks are found, go to next step. If any exhaust gas leaks are found, repair or replace faulty exhaust system components as necessary. After repair, go to step 7.
4. Inspect Installation Of HO2S (Front) & HO2S (Rear) - Turn ignition off. Inspect front and rear HO2Ss for looseness. If no problem is found, go to next step. If problem is found, resecure suspect front or rear HO2S and/or repair exhaust leak as necessary. After repair, go to step 7.
5. Inspect HO2S (Front) Voltage - Start engine and let idle until normal operating temperature is reached. Using scan tool, access O2S11 PID. Verify O2S11 PID while racing engine (in park). Ensure that each PID reading is within following conditions: More than 0.45 volt when suddenly depressing accelerator pedal (rich condition). Less than 0.45 volt just after release of accelerator pedal (lean condition). If O2S11 PID readings are as specified, go to next step. If any O2S11 PID reading is not as specified, replace suspect H2OS. After repair, go to step 7.
6. Check TWC - Turn ignition off. Allow exhaust system to cool down. Remove TWC and perform inspection. See «WARM UP THREE-WAY CATALYTIC CONVERTER»(ref-151892-S18732369482003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If problem is found, replace TWC. After repair, go to next step. If no problem is found, replace rear HO2S. After repair, go to next step.
7. Verify Troubleshooting Of DTC P0420 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and perform DRIVE MODES 1, 2 and 3. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM.Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0420 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Verify Related Pending Code Or Stored DTCs - Stop engine and leave ignition on. Monitor for DTC P0441 or pending coderelated to this DTC. If no other DTC is present, go to next step. If other DTC related to this DTCis present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Determine If Leak Concern Or Blockage Concern - Perform evaporative system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If system passed (Green light), go to next step. If system failed (Red light), go to step 5.
4. Inspect Purge Solenoid Valve Stuck Closed - Check if purge solenoid valve is stuck closed. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, ensure vacuum hoses between intake manifold and charcoal canister, catch tank or charcoal canister are not plugged. Repair or replace as necessary. After repair, go to step 10. If purge solenoid valve is not okay, replace purge solenoid valve. After repair, go to step 10.
5. Locate Leak Point - Using ultrasonic leak detector, check following: Charcoal canister. Catch tank. Fuel filler cap. EVAP hoses and pipes. Fuel tank. If leak is not detected, go to next step. If leak is detected, repair or replace as necessary. After repair, go to step 9.
6. Inspect EVAP System Leak Detection Pump - Connect all disconnected connectors and hoses. Install clamp on EVAP system leak detection pump hose between EVAP system leak detection pump and air filter. Perform EVAP system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result passed (Green light on), go to next step. If test result failed (Red light on), go to step 8.
7. Confirm EVAP System Leak Detection Pump Leakage - Remove clamp from EVAP system. Perform EVAP system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result passed (Green light on), go to next step. If test result failed (Red light on), replace EVAP system leak detection pump. After repair, go to step 9.
8. Inspect Fuel Pump Unit Installation - Remove fuel tank. Check for damage, insufficient sealing or incorrectly installed fuel pump unit. If no problems are found, go to next step. If problem is found, repair or replace fuel tank or sealing. After repair, go to next step.
9. Perform Leak Inspection - Connect all disconnected connectors and hoses. Perform EVAP system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result failed (Red light on), leakage is still present. Locate leak and repair. After repair, go to next step. If test result passed (Green light on), go to next step.
10. Verify Troubleshooting Of DTC P0441 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Perform DRIVE MODE 4. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P0441 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 18.
2. Inspect For Other DTCs - Leave ignition on. Monitor for other DTCs. If malfunction code recordedis P0442, go to next step. If malfunction code(s) recordedare P0443 and/or P1449, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000). NOTE: When fuel filler caps other than OEM caps are attached, it is considered malfunction.
3. Inspect Fuel Filler Cap - Turn ignition off. Inspect fuel filler cap for installation (loose) or damage. If fuel filler cap is properly install and no damage is found, go to next step. If fuel filler cap is faulty, either reinstall properly or replace fuel filler cap. After repair, go to step 18.
4. Inspect Whole System Of EVAP System - Perform Whole System Inspection of EVAP system, see «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If scan tool value holds for a minimum of 2 minutes, no leaks were detected in EVAP control system. Go to step 14. If scan tool does not hold value for a minimum of 2 minutes and an evaporative emission tester is available, go to step 13. If tester is not available, go to next step.
5. Inspect Leakage From Charcoal Canister To Fuel Tank - Inspect for leak from charcoal canister to fuel tank. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If scan tool does not drop to less than specified and hold value for a minimum of 2 minutes, go to next step. If scan tool value drops to less than specified and holds for a minimum of 2 minutes, go to step 8.
6. Inspect Attached Accessories On Fuel Tank - Remove fuel tank and visually inspect for damage, insufficient sealing, or poorly attached accessories on fuel tank, such as fuel gauge. If fuel tank and accessories are okay, go to next step. If fuel tank accessories are faulty, repair or replace fuel tank or sealing as necessary. After repair, go to step 14. NOTE: Rollover valve is an integral part of fuel tank. If rollover valve is faulty, replace fuel tank.
7. Inspect Rollover Valve - With fuel tank removed, inspect rollover valves. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If rollover valve is okay, inspect hoses from charcoal canister to fuel tank for detached, incorrectly installed or cracked, repair or replace hoses if necessary. After repair, go to step 14. If rollover valve is faulty, replace rollover valve. After repair, go to step 14.
8. Inspect Leakage From Charcoal Canister To Purge Solenoid Valve - Inspect leak from charcoal canister to purge solenoid valve. If vacuum drops to less than specified reading and holds for a minimum of 2 minutes, go to step 14. If vacuum does not drop to less than specified reading and hold for a minimum of 2 minutes, go to next step.
9. Inspect Catch Tank - Remove catch tank. Plug one port, using vacuum pump apply vacuum at other port. Inspect for plugging, damage or pinhole leaks. If catch tank is okay, go to next step. If catch tank is faulty, replace catch tank. After repair, go to step 14.
10. Inspect Purge Solenoid Valve - Remove purge solenoid valve and perform inspection. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, go to next step. If purge solenoid valve is faulty, replace purge solenoid valve. After repair, go to step 14.
11. Inspect Charcoal Canister - Remove charcoal canister. Inspect for plugging, damage or pinhole leaks. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If charcoal canister is okay, go to next step. If charcoal canister is faulty, replace charcoal canister. After repair, go to step 14.
12. Inspect CDCV - Remove CDCV and perform inspection. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CDCV is okay, inspect hoses from charcoal canister to CDCV for being detached, incorrect installation or cracking. Repair or replace if necessary. After repair, go to step 14. If CDCV is faulty, replace CDCV. After repair, go to step 14.
13. Inspect Leakage Of EVAP Control System - Inspect EVAP control system for leaks using evaporative emission tester. See «FUEL-FILLER CAP INSPECTION»(ref-151892-S34460409592003010900000) under FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If component is okay, go to next step. If component is faulty, replace component. After repair, go to next step.
14. Verify EVAP System Repaired - Return vehicle to original condition. Implement Evaporative Emission System Tester Self Test and Leak Inspection, even if vehicle is not in test condition. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.If EVAP system small leak test is faulty, go to next step. If EVAP system small leak test is okay, go to step 18.
15. Decide On After Repair Procedure According To Repair Shop Condition - Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Check if repair shop conditions are appropriate to perform Drive Mode 4. If shop conditions are not okay, go to next step. If shop conditions are okay, go to step 17.
16. Verify EVAP System Repaired By EVAP System Test - With no DTCs stored in PCM memory, implement Evaporative Emission System Tester Self Test and Leak Inspection again. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.If system test result is not okay, replace PCM. After repair, go to step 18. If system test result is okay, go to step 18.
17. Monitor EVAP System By Drive Mode 4 - Run EVAP System Repair Verification Drive Mode 4. See «MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE»(ref-151884-S16556198142003010900000) under DRIVE MODES. Stop vehicle. Using scan tool, access ON BOARD SYSTEM READINESS TEST to inspect Drive Mode completion status. If EVAPORATIVE PURGE SYSTEM has been monitored, go to next step. If EVAPORATIVE PURGE SYSTEM has not been monitored, go back to step 15.
18. Verify EVAP System Repaired - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Access DIAGNOSTIC MONITORING TEST RESULTS of generic OBD-II functions and verify TEST ID 10:21:00 value. If test result is less than maximum value, go to next step. If test result is not less than maximum value, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
19. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 10.
2. Classify Intermittent Concern Or Continuous Concern - Leave ignition on. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If DTC P0443 is present again, go to next step. If same DTC is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Classify Open Circuit Or Short To Ground Malfunction - Turn ignition off. Disconnect purge solenoid valve vacuum hose that is connected to intake manifold. Connect vacuum pump to purge solenoid valve. Turn ignition on, engine off. Pump vacuum several times and wait a few seconds. If purge solenoid valve does not hold vacuum, go to next step. If purge solenoid valve holds vacuum, go to step 5.
4. Inspect Passage Control Of Purge Solenoid Valve - Turn ignition off. Disconnect purge solenoid valve harness connector. (Scheme 28) With vacuum pump still connected, pump vacuum pump several times and wait for few seconds. If purge solenoid valve holds vacuum, repair short to ground in Green/Yellow wire between purge solenoid valve harness connector terminal "B" and PCM 24-pin harness connector terminal "3C". After repair, go to step 10. If purge solenoid valve does not hold vacuum, replace purge solenoid valve. After repair, go to step 10.
5. Inspect Poor Connection Of Purge Solenoid Valve Connector - With purge solenoid valve harness connector disconnected, check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 10.
6. Inspect Purge Solenoid Valve - Measure resistance between purge solenoid valve connector terminals "A" and "B". Resistance should be 22-26 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace purge solenoid valve. After repair, go to step 10.
7. Inspect Purge Solenoid Valve Power Supply Circuit For Open - Turn ignition on, engine off. Measure voltage between ground and purge solenoid valve harness connector terminal "A" (White/Red wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open circuit in White/Red wire between purge solenoid valve harness connector terminal "A" and main relay 4-pin harness connector terminal "D". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
8. Inspect Poor Connection Of PCM Connector - Turn ignition off. Disconnect PCM 24-pin harness connector. (Scheme 28) Check for poor connection due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 10.
9. Inspect Purge Solenoid Valve Control Circuit For Open - Reconnect purge solenoid valve harness connector and leave PCM 24-pin harness connector disconnected. Turn ignition on, engine off. Measure voltage between ground and PCM 24-pin harness connector terminal "3C" (Green/Yellow wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open circuit in Green/Yellow wire between purge solenoid valve harness connector terminal "B" and PCM 24-pin harness connector terminal "3C". After repair, go to next step.
10. Verify Troubleshooting Of DTC P0443 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition on, engine off. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0443 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 28

Diagnostic Procedures

1. Verify Related Repair Information Availability - Record freeze frame data. Check for service bulletins and on-line information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 4 .
2. Check EVAP System Leak Detection Pump Circuit For Short To Power - Turn ignition on, engine off. Disconnect EVAP system leak detection pump 4-pin harness connector. Measure voltage between ground and EVAP system leak detection pump 4-pin harness connector terminal "D" (Yellow/Black wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If battery voltage is not present, go to next step. If battery voltage is present, repair short to power in Yellow/Black wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3K". After repair, go to step 4 .
3. Inspect COV (EVAP System Leak Detection Pump) - Check COV in EVAP leak detection pump. Perform EVAP system leak detection pump inspection. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If COV is okay, go to next step. If COV is faulty, replace EVAP system leak detection pump. After repair, go to next step.
4. Verify Troubleshooting Of DTC P0446 Completed - Reconnect all disconnected connectors. Turn ignition on, engine off. Using scan tool, clear DTC. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition off. Run EVAP System Repair Verification Drive Mode 4. See «MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE»(ref-151884-S16556198142003010900000) under DRIVE MODES. Recheck DTCs. If DTC P0446 is present, replace PCM. After repair, go to next step. If DTC P0446 is not present, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition off, then on (engine off). Verify related PENDING CODE or stored DTCs. If no other DTC is present, go to next step. If other DTC related to this DTCis present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Classify Intermittent Or Continuous Concern - Perform evaporative system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK DETECTOR»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If system test result failed (Red light turns on), go to next step. If system test result passed (Green light turns on), intermittent concern exists. Inspect purge solenoid valve and EVAP system leak detection pump circuit for intermittent concern. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
4. Locate Leak Point - Check for leakage at following using Ultrasonic leak detector: Charcoal canister. Catch tank. Fuel filler cap. EVAP hoses and pipes. Fuel tank. If leakage is not present, go to next step. If leakage is present, repair leakage or replace part. After repair, go to step 9.
5. Inspect Purge Solenoid Valve - Inspect if purge solenoid valve is stuck closed. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, go to next step. If purge solenoid valve is faulty, replace purge solenoid valve. After repair, go to step 9.
6. Inspect EVAP System Leak Detection Pump - Return vehicle to original condition. Place clamp on EVAP system leak detection pump hose between EVAP system leak detection pump and air filter. Perform evaporative system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK DETECTOR»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result passed (Green light turns on), go to next step. If test result failed (Red light turns on), go to step 8.
7. Confirm EVAP System Leak Detection Pump Leakage - Remove clamp from EVAP system leak detection pump hose. Perform evaporative system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK DETECTOR»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result passed, go to next step. If test result failed (Red light turns on), replace EVAP system leak detection pump. After repair, go to step 9.
8. Inspect Fuel Pump Unit Installation - Remove fuel tank. Visually inspect for damage, insufficient sealing or poorly installed pump unit. If no problem is found, go to next step. If problem is found, repair or replace fuel tank or seal. After repair, go to next step.
9. Perform Leak Inspection - Return vehicle to original condition. Perform evaporative system leak inspection. See «EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK DETECTOR»(ref-151892-S27056453472003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If test result passed (Green light turns on), go to next step. If test result failed (Red light turns on), leakage still exists. Locate leak point and repair as necessary. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 3.
2. Inspect Fuel Gauge Sender Unit - Turn ignition off. Inspect fuel sending unit. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If fuel sending unit is faulty, replace fuel sending unit and go to next step. If fuel sender unit is okay, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
3. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect Terminals For Poor Connection - Turn ignition off. Disconnect fuel gauge sending unit 4-pin harness connector. (Scheme 29) Check for poor connection at terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary and go to step 6.
3. Classify Fuel Gauge Sender Unit Or Harness Malfunction - Inspect fuel gauge sending unit. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If fuel gauge sending unit is okay, go to next step. If fuel gauge sending unit is faulty, replace fuel gauge sending unit. After repair, go to step 6.
4. Inspect Fuel Level Signal Circuit For Short To GND - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 29) Check continuity between ground and fuel gauge sending unit 4-pin harness connector terminal "C" (Brown/Black wire). If continuity is not found, go to next step. If continuity is found, repair short circuit to ground in Brown/Black wire between fuel gauge sending unit4-pin harness connector terminal "C" and PCM 31-pin harness connector terminal "4AD". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 6.
5. Inspect Fuel Gauge Sender Unit Circuits For Shorts - Check continuity between fuel gauge sending unit 4-pin harness connector terminals "A" (Black wire) and "C" (Brown/Black wire). If continuity is not found, go to next step. If continuity is found, repair short between fuel gauge sending unit ground and signal circuits (Brown/Black and Black wires). After repair, go to next step.
6. Verify Troubleshooting Of DTC P0462 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0462 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 29

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Inspect Fuel Gauge Sender Unit Connector For Poor Connection - Turn ignition off. Disconnect fuel gauge sending unit 4-pin harness connector. (Scheme 29) Check for poor connection at terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7.
3. Classify Fuel Gauge Sender Unit Or Harness Malfunction - Inspect fuel sending unit. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If fuel gauge sending unit is okay, go to next step. If fuel sending unit is faulty, replace fuel sending unit. After repair, go to step 7.
4. Inspect FTL Signal Circuit For Open - Turn ignition on, engine off. Measure voltage between ground and fuel gauge sending unit harness connector terminal "C" (Brown/Black wire). Voltage reading should be 4.5-5.5 volts. If voltage reading is not as specified, go to next step. If voltage reading is as specified, go to step 7.
5. Inspect Poor Connection Of PCM Connector - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 29) Check for poor connection at terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7.
6. Inspect Fuel Gauge Sender Unit GND Circuit For Open - With fuel sending unit harness connector disconnected, check continuity between ground and fuel sending unit connector terminal "A" (Black Wire). If continuity is found, go to next step. If continuity is not found, repair open circuit in Black wire between fuel sending unit 4-pin harness connector terminal "A" and body ground. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
7. Verify Troubleshooting Of DTC P0463 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature its reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0463 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Check service bulletins for repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9. If repair information is not available, go to next step.
2. Determine If Intermittent Concern Or Continuous Concern - Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle. Turn A/C system on to operate cooling fan relay. Monitor for DTCs. If DTC P0480 is present again, go to next step. If DTCs are not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect Poor Connection Of Cooling Fan Relay - Turn ignition off. Disconnect cooling fan relay 4-pin harness connector. (Scheme 30) Check for poor connection at terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 9.
4. Inspect Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between ground and cooling fan relay 4-pin harness connector terminal "A" (Black/White wire). Voltage reading should be battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair open or short circuit in Black/White wire between under-dash fuse block and cooling fan relay 4-pin harness connector. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
5. Inspect Cooling Fan Relay - Turn ignition off. Inspect cooling fan relay. See appropriate ELECTRIC COOLING FANS article in ENGINE COOLING. If cooling fan relay is okay, go to next step. If cooling fan relay is faulty, replace fan relay. After repair, go to step 9.
6. Inspect Poor Connection Of PCM Connector - Disconnect PCM 17-pin harness connector. (Scheme 30) Check for poor connection at PCM 17-pin harness connector terminal "2B" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 9.
7. Inspect Control Circuit For Short - Check continuity between ground and cooling fan relay 4-pin harness connector terminal "E" (Red/Yellow wire). If continuity is present, repair short circuit to ground in Red/Yellow wire between cooling fan relay 4-pin harness connector terminal "E" and PCM 17-pin harness connector terminal "2B". After repair, go to step 9. If continuity is not present, measure voltage between ground and cooling fan relay 4-pin harness connector terminal "E". If battery voltage is present, repair short circuit to power in Red/Yellow wire between cooling fan relay 4-pin harness connector terminal "E" and PCM 17-pin harness connector terminal "2B". After repair, go to next step. If about zero volts are present, go to next step.
8. Inspect Control Circuit For Open Circuit - Check continuity between cooling fan relay 4-pin harness connector terminal "E" and PCM 17-pin harness connector terminal "2B" (Red/Yellow wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Red/Yellow wire between cooling fan relay 4-pin harness connector terminal "E" and PCM 17-pin harness connector terminal "2B". After repair, go to next step.
9. Verify Troubleshooting Of DTC P0480 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and turn A/C system on to operate cooling fan relay. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0480 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 30

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 17.
2. Classify VSS Side Or PCM Side Malfunction - Start engine and drive vehicle. Check for speedometer needle to move while driving. If speedometer needle moves when driving, go to next step. If speedometer needle does not move when driving. For vehicle equipped with manual transmission (M/T), go to step 7. For vehicle equipped with automatic transmission (A/T), go to step 11.
3. Verify DTC P0500 Present - Stop engine and leave ignition on. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Access LOAD and RPM PIDs. Drive vehicle for about 25.6 seconds or more under following conditions: LOAD PID: 40 percent or more. RPM PID: 2000 RPM or more. Monitor for DTCs. If same DTC P0500 is present, go to next step. If DTC P0500 is not present, go to step 5.
4. Inspect Vehicle Speed Signal Circuit For Short To GND - Turn ignition off. Disconnect cruise control module 20-pin harness connector, instrument cluster 16-pin harness connector and PCM 24-pin harness connector. (Scheme 31) Check continuity between ground and PCM 24-pin harness connector terminal "3T" (Green/Red wire). If continuity is present, repair short circuit to ground in Green/Red wire between cruise control module 20-pin harness connector terminal "P" and PCM 24-pin harness connector terminal "3T". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 17. If continuity is not present, replace speedometer. After repair, go to step 17.
5. Inspect PCM Connector For Poor Connection - Disconnect PCM 24-pin harness connector. Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 17.
6. Inspect PCM Circuit For Open Circuit - Disconnect instrument cluster 16-pin harness connector. Check continuity in Green/Red wire between PCM 24-pin harness connector terminal "3T" and instrument cluster 16-pin harness connector terminal "2L". If continuity is present, go to step 17. If continuity is not present, repair open circuit in Green/Red wire between PCM 24-pin harness connector terminal "3T" and instrument cluster 16-pin harness connector terminal "2L". After repair, go to step 17.
7. Inspect Vehicle Speed Signal Circuit At Instrument Cluster For Open Circuit - Disconnect VSS harness connector. (Scheme 31) Check continuity between harness connector terminals as follows: Between VSS harness connector terminal "A" and instrument cluster 16-pin harness connector terminal "2M" (Orange wire). Between VSS harness connector terminal "B" and instrument cluster 16-pin harness connector terminal "1M" (Yellow wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire between instrument cluster 16-pin harness connector and VSS harness connector. After repair, go to step 17.
8. Inspect Vehicle Speed Signal Circuit At Instrument Cluster Circuit For Short - Check continuity between VSS harness connector terminals "A" (Orange wire)and "B" (Yellow wire). If continuity is not present, go to next step. If continuity is present, repair short circuit between VSS circuits. After repair, go to step 17.
9. Inspect Vehicle Speed Signal At Instrument Cluster For Short To GND - Check continuity at instrument cluster connector terminals as follows: Between ground and instrument cluster 16-pin harness connector terminal "1M" (Yellow wire). Between ground and instrument cluster 16-pin harness connector terminal "2M" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in suspect wire between instrument cluster 16-pin harness connector and VSS harness connector. After repair, go to step 17.
10. Inspect VSS Output Voltage - Remove VSS. Inspect voltage between VSS connector terminals "A" and "B". For proper component testing, see «VEHICLE SPEED SENSOR»(ref-151892-S18953781802003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If voltage reading is as specified, inspect speedometer. After repair, go to step 17. If voltage reading is not as specified, replace VSS. After repair, go to step 17.
11. Inspect Vehicle Speed Signal At Instrument Cluster For Short To GND - Disconnect TCM 35-pin harness connector. (Scheme 31) Check continuity between ground and TCM 35-pin harness connector terminal "AC" (Black/White wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Black/White wire between instrument cluster 16-pin harness connector terminal "2M" and TCM 35-pin harness connector terminal "AC". After repair, go to step 17.
12. Inspect Vehicle Speed Signal At Instrument Cluster Circuit For Open Circuit - Check continuity between instrument cluster 16-pin harness connector terminal "2M" and TCM 35-pin harness connector terminal "AC" (Black/White wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/White wire between instrument cluster 16-pin harness connector terminal "2M" and TCM 35-pin harness connector terminal "AC" (Black/White wire). After repair, go to step 17.
13. Inspect Output Speed Signal At TCM For Open Circuit - Disconnect output speed sensor harness connector. (Scheme 31) Check continuity between TCM 35-pin harness connector and output speed sensor harness connector terminals as follow: Between output speed sensor harness connector terminal "A" and TCM 35-pin harness connector terminal "AE" (Yellow wire). Between output speed sensor harness connector terminal "B" and TCM 35-pin harness connector terminal "AF" (Orange wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire between output speed sensor harness connector and TCM 35-pin harness connector. After repair, go to step 17.
14. Inspect Output Speed Signal Circuit At TCM For Short - Check continuity between output speed sensor harness connector terminals "A" (Yellow wire) and "B" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short circuit between output speed sensor circuits. After repair, go to step 17.
15. Inspect Vehicle Speed Signal At TCM For Short To GND - Check continuity at TCM 35-pin harness connector terminals as follows: Between ground and TCM 35-pin harness connector terminal "AE" (Yellow wire). Between ground and TCM 35-pin harness connector terminal "AF" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short to ground in suspect circuit between body ground and TCM 35-pin harness connector. After repair, go to step 17.
16. Inspect Output Speed Sensor Resistance - Measure resistance between output speed sensor connector terminals "A" and "B". Resistance reading should be 387-473 ohms at 68°F (20°C). If resistance reading is as specified, inspect vehicle speedometer. After repair, go to next step. If resistance reading is not as specified, replace output speed sensor. After repair, go to next step.
17. Verify Troubleshooting Of DTC P0500 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Access LOAD and RPM PIDs. Drive vehicle under following conditions: LOAD PID: 40 percent or more. RPM PID: 2000 RPM or more. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0500 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
18. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 31

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 13.
2. Classify Intermittent Concern Or Continuous Concern - Stop engine and leave ignition on. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If DTC P0505 is present again, go to next step. If DTC P0505 is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Inspect IAC Valve Connector For Poor Connection - Turn ignition off. Disconnect IAC valve harness connector. (Scheme 32) Check for poor connection at IAC valve harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 13.
4. Inspect IAC Valve Electrical Malfunction - With IAC valve harness connector disconnected, measure resistance between IAC valve connector terminals "A" and "B". Resistance reading should be 8.7-10.5 ohms at 75°F (24°C). If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace IAC valve. After repair, go to step 13.
5. Determine If Malfunction At Power Supply Circuit Or Control Circuit - Turn ignition on, engine off. Measure voltage between ground and IAC valve harness connector terminal "A" (Orange wire). If battery voltage is not present, malfunction is at power supply circuit. Go to next step. If battery voltage is present, malfunction is at control circuit. Go to step 9.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 17-pin harness connector. (Scheme 32) Check for poor connection at PCM connector terminals "2P" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 13.
7. Inspect Power Circuit For Short To GND - Check continuity between ground and IAC valve harness connector terminal "A" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Orange wire between IAC valve harness connector terminal "A" and PCM 17-pin harness connector terminal "2P". After repair, go to step 13.
8. Inspect Power Circuit For Open Circuit - Check continuity between IAC valve harness connector terminal "A" and PCM 17-pin harness connector terminal "2P" (Orange wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Orange wire between IAC valve harness connector terminal "A" and PCM 17-pin harness connector terminal "2P". After repair, go to step 13.
9. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 17-pin harness connector. Check for poor connection at PCM connector terminals "2Q" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 13
10. Inspect Control Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and IAC valve harness connector terminal "B" (Violet/Red wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short to power in Violet/Red wire between IAC valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2Q". After repair, go to step 13.
11. Inspect Control Circuit For Short To GND - Turn ignition off. Check continuity between ground and IAC valve harness connector terminal "B" (Violet/Red wire). If continuity is not present, go to next step. If continuity is present, repair short to ground in Violet/Red wire between IAC valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2Q". After repair, go to step 13.
12. Inspect Control Circuit Malfunction For Open Circuit - Check continuity between IAC valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2Q" (Violet/Red wire). If continuity is found, go to next step. If continuity is not present, repair open circuit in Violet/Red wire between IAC valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2Q". After repair, go to next step.
13. Verify Troubleshooting Of DTC P1504 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0505 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
14. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 32

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 10.
2. Verify Related Pending Or Stored DTCs - Turn ignition off, then on (engine off). Using scan tool. Monitor for pending codes or other DTCs stored in PCM memory. If no pending or other DTCs are present, go to next step. If pending code or other DTCs are present, follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Inspect IAC Valve Malfunction - Turn ignition off. Inspect IAC valve for proper operation. See «IDLE AIR CONTROL VALVE»(ref-151892-S00574935032003010900000) under IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If IAC valve is okay, go to next step. If IAC valve is faulty, replace IAC valve. After repair, go to step 10.
4. Inspect A/C Magnet Clutch Operation - Turn blower motor switch off and check A/C magnetic clutch operation. If magnetic clutch turns off, go to next step. If magnetic clutch remains on, malfunction in A/C system is present. For proper diagnostic procedure, see «A/C IS ALWAYS ON OR COMPRESSOR RUNS CONTINUOUSLY»(ref-151888-S22448674242003010900000) under SYMPTOM DIAGNOSIS in TROUBLESHOOTING - NO CODES article. After repair, go to step 10.
5. Inspect Generator Control Circuit Malfunction - Turn ignition off. Disconnect generator harness connector. (Scheme 33) Turn ignition on. Measure voltage between ground and generator harness connector terminal "D" (Gray/Red wire). If no voltage is present, go to next step. If voltage is present, repair short to power circuit in Gray/Redwire between generator harness connector terminal "D" and PCM 24-pin harness connector terminal "3M". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
6. Inspect Purge Solenoid Valve Control Malfunction - Turn ignition off. Remove purge solenoid valve, check for damage and perform Purge Solenoid Valve - Airflow Inspection. See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, go to next step. If purge solenoid valve is faulty, replace purge solenoid valve. After repair, go to step 10.
7. Inspect Air Cleaner Element - Start engine and let idle. Remove air cleaner element while engine is running. If engine speed does not increase, go to next step. If engine speed increases, replace air cleaner element. After repair, go to step 10.
8. Inspect Throttle Body Passage - Turn ignition off. Inspect throttle body for clogged passages and contaminated throttle valve. If throttle body is okay, go to next step. If throttle body is clogged or contaminated, clean, repair or replace throttle body as necessary. After repair, go to step 10.
9. Inspect Engine Compression - Return vehicle to original condition. Perform engine compression test. For proper engine compression test, see «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES article. Compression should be about 198 psi (13.9 kg/cm 2 ) at 300 RPM. If engine compression is as specified, go to next step. If engine compression is not as specified, determine source of low compression. Repair as necessary. After repair, go to next step.
10. Verify Troubleshooting Of DTC P0506 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Depress brake pedal for 14.1 or more seconds. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0506 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 33

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition off, then on (engine off). Using scan tool. Monitor for related pending codes or other DTCs stored in PCM memory. If no pending codes or other DTCs are present, go to next step. If pending codes or other DTCs are present follow appropriate DTC diagnostic procedure. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151884-S06753801942003010900000).
3. Inspect IAC Valve Malfunction - Inspect IAC valve for proper operation. See «IDLE AIR CONTROL VALVE»(ref-151892-S00574935032003010900000) under IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If IAC valve is okay, go to next step. If IAC valve is faulty, replace IAC valve. After repair, go to step 7.
4. Inspect Accelerator Cable Free Play - Turn ignition off. Check throttle cable free play. Ensure throttle valve position is fully closed. Throttle cable free play should be.04-.11" (1-3 mm). If adjustment is as specified, go to next step. If adjustment is not as specified, adjust throttle cable free play as necessary. After repair, go to step 7.
5. Inspect Vacuum Hose Connection - Inspect vacuum hoses for condition, misrouted and good connection. See «VACUUM DIAGRAMS»(ref-151899) article. If vacuum hoses are okay, go to next step. If vacuum hoses are damaged, misrouted or not connected properly, repair or replace as necessary. After repair, go to step 7.
6. Visual Inspect Throttle Valve - Turn ignition off. Remove throttle body and ensure throttle valve closes fully. Inspect throttle body for clogged passages and contaminated throttle valve. If throttle body is okay, go to next step. If throttle valve is not closing fully or throttle body is clogged or contaminated, clean or replace throttle body as necessary. After repair, go to next step.
7. Verify Troubleshooting Of DTC P0507 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Depress brake pedal for 14.1 or more seconds. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0507 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 4.
2. Inspect PSP Switch - Turn ignition off. Inspect PSP switch operation. See «POWER STEERING PRESSURE SWITCH»(ref-151892-S01306177172003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PSP switch is okay, go to next step. If PSP switch is faulty, replace PSP switch. After repair, go to step 4.
3. Inspect PSP Switch Signal Circuit For Short To GND - Turn ignition off. Disconnect PSP switch and PCM 31-pin harness connectors. (Scheme 34) Check continuity between ground and PSP switch connector terminal "A" (Brown wire). If continuity is not present, go to next step. If continuity is present, repair short to ground in Brown wire between PSP switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4C". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
4. Verify Troubleshooting Of DTC P0550 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Drive vehicle more than 37.3 MPH for one minute. Verify ECT PID is more than 140°F (60°C). Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0550 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 34

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7 .
2. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7 .
3. Check Serial Communication Circuit At PCM Connector - Turn ignition off. Disconnect PCM 31-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and PCM 31-pin harness connector terminal "4Z" (Pink/Black wire). Voltage reading should be 4.5-5.5 volts. If voltage reading is as specified, go to next step. If voltage reading is not as specified, check for open or short in Pink/Black wire between PCM 31-pin harness connector terminal "4Z" and TCM 36-pin harness connector terminal "O". Repair or replace as necessary. After repair, go to step 7 .
4. Inspect TCM Connector For Poor Connection - Turn ignition off. Disconnect TCM 36-pin harness connector. Check for poor connection at TCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7 .
5. Inspect Serial Communication Circuit At TCM Connector - Turn ignition off. Reconnect PCM 31-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and TCM 36-pin harness connector terminal "AL" (Violet/Green wire). If voltage reading is 4.5-5.5 volts, go to next step. If voltage reading is as specified, go to next step. If voltage reading is not as specified, check for open or short circuit in Violet/Green wire between TCM 36-pin harness connector terminal "AL" and PCM 31-pin harness connector terminal "4AC". After repair, go to step 7 .
6. Inspect TCM - Turn ignition off. Reconnect TCM 36-pin harness connector. Perform TCM DTC inspection and voltage inspection. See appropriate article in AUTOMATIC TRANSMISSIONS. If TCM is okay, go to next step. If TCM if faulty, replace TCM. After repair, go to next step.
7. Verify Troubleshooting Of DTC P0600 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0600 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000) . If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Perform DTC Confirmation Procedure - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Perform KOEO Self-Test. If same P0605 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step. If no DTC is present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
2. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect Brake Switch Signal Circuit For Short To Power - Turn ignition off. Disconnect brake switch harness connector. (Scheme 35) Turn ignition on, engine off. Measure voltage between ground and brake switch harness connector terminal "B" (Green wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to voltage in Green wire between brake switch harness connector terminal "B" and PCM 31-pin harness connector terminal "4B". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
3. Inspect Brake Switch Connector For Poor Connection - Turn ignition off. Check for poor connection at brake switch harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
4. Inspect Brake Switch Power Circuit For Open - Turn ignition on, engine off. Measure voltage between ground and brake switch harness connector terminal "A" (White/Green wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open or short circuit in White/Green wire between engine compartment main fuse block and brake switch harness connector terminal "A". After repair, go to step 8.
5. Inspect Poor Connection Of PCM Connector - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 35) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
6. Inspect Brake Switch Signal Circuit For Open - Reconnect brake switch harness connector. Turn ignition on, engine off. While depressing brake pedal measure voltage between ground and PCM 31-pin harness connector terminal "4B" (Green wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open or short circuit in Green wire between brake switch harness connector terminal "B" and PCM 31-pin harness connector terminal "4B". After repair, go to step 8.
7. Inspect Brake Switch - Turn ignition off. Perform brake switch inspection. See «BRAKELIGHT SWITCH»(ref-151892-S00360292682003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If brake switch is okay, go to next step. If brake switch is faulty, replace brake switch. After repair, go to next step.
8. Verify Troubleshooting Of DTC P0703 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Drive vehicle at 18.6 MPH or more. Depress and release brake pedal 10 times or more during test drive. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0703 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 35

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Inspect Clutch Switch Signal Circuit For Short To GND - Turn ignition off. Disconnect clutch switch harness connector. (Scheme 36) Measure voltage between ground and brake switch harness connector terminal "A" (White/Green wire). If voltage is not present, go to next step. If voltage is present, repair short circuit to ground in White/Green wire between clutch switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4I". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 7.
3. Inspect Clutch Switch Connector For Poor Connection - Turn ignition off. Check for poor connection at clutch switch connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7.
4. Inspect Clutch Switch GND Circuit For Open - Check continuity between ground and clutch switch harness connector terminal "B" (Black wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between clutch switch harness connector terminal "B" and body ground joint connector "JC-01". After repair, go to step 7.
5. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 36) Check for poor connection at PCM 31-pin harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 7.
6. Inspect Clutch Switch Signal Circuit For Open - Check continuity between clutch switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4I" (White/Green wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in White/Green wire between clutch switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4I". After repair, go to next step.
7. Verify Troubleshooting Of DTC P0704 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Drive vehicle at 18.6 MPH or more. Depress and release clutch pedal 10 times or more during test drive. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0704 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 36

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
2. Inspect Neutral Switch Signal Circuit For Short To GND - Turn ignition off. Disconnect neutral switch single pin harness connector terminal "A". (Scheme 37) Measure voltage between ground and neutral switch harness connector terminal "A" (Violet wire). If voltage is not present, go to next step. If voltage is present, repair short circuit to ground in Violet wire between neutral switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4H". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
3. Inspect Poor Connection Of Neutral Switch Connector - Disconnect single pin harness connector terminal "B" (Black wire). Check for poor connection at neutral switch single pin connectors terminals "A" and "B" due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
4. Inspect Neutral Switch GND Circuit For Open - Check continuity between ground and neutral switch harness connector terminal "B" (Black wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between neutral switch harness connector terminal "B" and body ground single ring terminal. After repair, go to step 8.
5. Inspect Poor Connection Of PCM Connector - Disconnect PCM 31-pin harness connector. (Scheme 37) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 8.
6. Inspect Neutral Switch Signal Circuit For Open - Check continuity between neutral switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4H" (Violet wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Violet wire between neutral switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4H". After repair, go to step 8.
7. Inspect Neutral Switch - Perform neutral switch inspection. See «NEUTRAL SWITCH (M/T)»(ref-151892-S40222397452003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If neutral switch is okay, go to next step. If neutral switch is faulty, replace neutral switch. After repair, go to next step.
8. Verify Troubleshooting Of DTC P0850 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Drive vehicle at 18.6 MPH or more. Shift up or down 14 times during test drive. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P0850 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 37

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 10.
2. Determine If Intermittent Concern Or Continuous Concern - Leave ignition on. Using scan tool. Monitor for DTCs. If DTC P1487 is present again, go to next step. If DTCs are not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Determine If Open Circuit Or Short To Ground Malfunction - Turn ignition off. Disconnect EGR boost sensor solenoid valve vacuum hose at solenoid port that connects to EGR valve. Connect vacuum pump to boost sensor solenoid valve. Apply vacuum and wait for 5 seconds. If EGR boost sensor solenoid valve does not hold vacuum, go to next step. If EGR boost sensor solenoid valve holds vacuum, go to step 5.
4. Inspect EGR Boost Sensor Solenoid Valve For Passage Control - Disconnect boost sensor solenoid valve 2-pin harness connector. (Scheme 38) Apply vacuum again and wait for 5 seconds. If EGR boost sensor solenoid valve holds vacuum, repair short circuit to ground in Gray/Black wire between EGR boost sensor solenoid valve harness connector terminal "B" and PCM 24-pin harness connector terminal "3D". After repair, go to step 10. If EGR boost sensor solenoid valve does not hold vacuum, replace EGR boost sensor solenoid valve. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
5. Inspect EGR Boost Sensor Solenoid Valve Connector For Poor Connection - Disconnect EGR boost sensor solenoid valve 2-pin harness connector. (Scheme 38) Check for poor connection at EGR boost sensor solenoid valve harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 10.
6. Inspect EGR Boost Sensor Solenoid Valve - Measure resistance between EGR boost sensor solenoid valve connector terminals "A" and "B". Resistance reading should be 23-27 ohms. If resistance reading is as specified, go to next step. If resistance reading is not as specified, replace EGR boost sensor solenoid valve. After repair, go to step 10.
7. Inspect EGR Boost Sensor Solenoid Valve Power Supply Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between ground and EGR boost sensor solenoid valve harness connector terminal "A" (White/Red wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White/Red wire between EGR boost sensor solenoid valve harness connector terminal "A" and main relay 4-pin harness connector terminal "D". After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 24-pin harness connector. (Scheme 38) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 10.
9. Inspect EGR Boost Sensor Solenoid Valve Control Circuit For Open - Reconnect EGR boost sensor solenoid valve harness connector. Turn ignition on, engine off. Measure voltage between ground and PCM 24-pin harness connector terminal "3D" (Gray/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Gray/Black wire between EGR boost sensor solenoid valve harness connector terminal "B" and PCM 24-pin harness connector terminal "3D". After repair, go to next step.
10. Verify Troubleshooting Of DTC P1487 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1487 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 38

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect Room Fuse - Turn ignition off. Inspect ROOM fuse (10-amp) for failure and proper installation, on inside vehicle fuse block. If ROOM fuse is okay, go to step 4. If ROOM fuse is faulty, go to next step. If ROOM fuse is incorrectly installed, reinstall correctly. After repair, go to step 6.
3. Inspect Monitor Circuit For Short To GND - Disconnect both battery cables. Measure resistance between ground and ROOM fuse left terminal. If resistance reading is more than 500 ohms, go to step 6. If resistance is less than 500 ohms, repair short to ground in Blue/Red wire between ROOM fuse left terminal and PCM 31-pin harness connector terminal "4AG". Replace ROOM fuse (10-amp). After repair, go to step 6. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.
4. Inspect PCM Connector For Poor Connection - Disconnect PCM 31-pin harness connector. (Scheme 39) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 6.
5. Inspect Monitor Circuit For Open - Disconnect both battery cables and PCM 31-pin harness connector. Check continuity between ROOM fuse left terminal and PCM 31-pin harness connector terminal "4AG" (Blue/Red wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Blue/Red wire between ROOM fuse left terminal and PCM 31-pin harness connector terminal "4G". After repair, go to next step.
6. Verify Troubleshooting Of DTC P1562 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1562 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 39

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 19. If repair information is not available, go to next step.
2. Determine If No DTC Detected Or Some DTC Detected - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If DTC P1624 is present, go to step 10. If DTC P1624 is not present, go to next step.
3. Inspect Immobilizer Unit Connector For Poor Connection - Turn ignition off. Disconnect immobilizer unit 12-pin harness connector. (Scheme 40) Check for poor connection at immobilizer unit 12-pin harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 19.
4. Inspect GND Circuit Of Immobilizer Unit For Open - Check continuity between ground and immobilizer unit 12-pin harness connector terminal "C" (Black wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between immobilizer unit 12-pin harness connector terminal "C" and body ground joint connectors (JC-01 and JC-02). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 19.
5. Inspect Coil Terminal - Disconnect coil 2-pin harness connector. (Scheme 40) Check for poor connection at coil connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 19.
6. Inspect Coil For Short Circuit - Check continuity between ground and coil connector terminal "A". If continuity is not present, go to next step. If continuity is present, replace coil. After repair, go to step 19.
7. Inspect Coil Circuit For Short - Reconnect coil 2-pin harness connector. Check continuity between ground and immobilizer unit 12-pin harness connector terminal "F" (Yellow/Green wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Yellow/Green wire between coil harness connector terminal "A" and immobilizer 12-pin harness connector terminal "F". After repair, go to step 19.
8. Inspect PCM Connector For Poor Connection - Disconnect PCM 24-pin harness connector. (Scheme 40) Check for poor connection at PCM 24-pin harness connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 19.
9. Inspect Communication Line For Open Circuit - Check continuity between immobilizer unit 12-pin harness connector terminal "A" and PCM 24-pin harness connector terminal "3S" (Red/Black wire). If continuity is present, go to step 19. If continuity is not present, repair open circuit in Red/Black wire between immobilizer unit 12-pin harness connector terminal "A" and PCM 24-pin harness connector terminal "3S". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 19.
10. Classify Malfunction By Other Detected DTCs - If DTC P1602 has not been detected with DTC P1624, go to next step. If DTC P1602 and P1624 has been detected, go to step 14.
11. Inspect Coil Connector For Poor Connection - Turn ignition off. Disconnect coil 2-pin harness connector. (Scheme 40) Check for poor connection at coil connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 19.
12. Inspect Coil For Open Circuit - Check continuity between coil connector terminals. If continuity is present, go to next step. If continuity is not present, replace coil. After repair, go to step 19.
13. Inspect Coil Circuit For Open Circuit - Reconnect coil 2-pin harness connector and disconnect immobilizer unit 12-pin harness connector. (Scheme 40) Check continuity between immobilizer unit 12-pin harness connector terminal "D" (Yellow/Red wire) and terminal "F" (Yellow/Green wire). If continuity is present, go to step 19. If continuity is not present, repair open circuit in Yellow/Red or Yellow/Green wire between coil harness connector and immobilizer unit 12-pin harness connector. After repair, go to step 19.
14. Determine If Malfunction By Another Detected DTC - Check for immobilizer unit DTC 03 (ID number is not input into immobilizer unit after cranking engine.). If immobilizer unit DTC 03 is not present, go to next step. If immobilizer DTC 03 is present, check key being used. Key has no transponder. Replace with registered key. After repair, go to step 19.
15. Determine If Malfunction By Another Detected DTC - Check for immobilizer unit DTC 01 (ID number unregistered in immobilizer unit is input after engine cranking.). If immobilizer unit DTC 01 is not present, go to next step. If immobilizer DTC 01 is present, check key being used. Key may not be programmed to immobilizer system. Reprogram key or use another programed key. For key reprogramming, see appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. After key is reprogrammed, go to next step.
16. Inspect Poor Connection Of Immobilizer Unit Connector - Turn ignition off. Disconnect immobilizer unit 12-pin harness connector. (Scheme 40) Check for poor connection at immobilizer unit connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are found faulty, repair or replace as necessary. After repair, go to step 19.
17. Inspect Immobilizer Unit Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between ground and immobilizer unit 12-pin harness connector terminal "J" (Blue/Red wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Blue/Red wire between immobilizer unit 12-pin harness connector terminal "J" and under-dash fuse block. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 19.
18. Inspect Communication Line For Short Harness - Turn ignition off. Check continuity between ground and immobilizer unit 12-pin harness connector terminal "A" (Red/Black wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Red/Black wire between immobilizer unit 12-pin harness connector terminal "A" and PCM 24-pin harness connector terminal "3S". After repair, go to next step.
19. Verify Troubleshooting Of DTC P1602 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1602 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
20. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 40

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 3.
2. Verify DTC P1603 Detected Again - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1603 is present, perform code word reprogram procedure. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. If same DTC P1603 is not present, go to next step.
3. Verify Troubleshooting Of DTC P1603 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1603 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
4. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 3.
2. Verify DTC P1604 Detected Again - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC P1604 is present, perform key ID number reprogram procedure. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. If same DTC P1603 is not present, go to next step.
3. Verify Troubleshooting Of DTC P1604 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1604 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
4. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 3 . If repair information is not available, go to next step.
2. Inspect Output Device Control Circuit For Short To Power - Turn ignition off. Disconnect harness connector of following output devices. Turn ignition on and measure voltage at indicated connector terminals: Between ground and EGR boost sensor solenoid valve 2-pin harness connector terminal "B" (Gray/Black wire). Between ground and EGR valve 6-pin harness connector terminal "A" (White/Green wire). Between ground and EGR valve 6-pin harness connector terminal "B" (Pink/Black wire). Between ground and EGR valve 6-pin harness connector terminal "E" (Light Green wire). Between ground and EGR valve 6-pin harness connector terminal "F" (Pink wire). Between ground and purge solenoid valve 2-pin harness connector terminal "B" (Green/Yellow wire). Between ground and VTCS solenoid valve 2-pin harness connector terminal "B" (Black/White wire). Voltage reading should be about zero volts. If all voltage readings are as specified, go to next step. If any voltage reading is not as specified, repair short circuit to power at appropriate output devices control circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
3. Verify Troubleshooting Of DTC P1608 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1608 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
4. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000) . If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 3.
2. Verify DTC P1621 Detected Again - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition off, then start engine. Monitor for DTCs. If same DTC P1621 is not present, go to next step. If same DTC P1621 is present, perform code word reprogram procedure. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
3. Verify Troubleshooting Of DTC P1603 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1621 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
4. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 4.
2. Verify DTC P1622 Detected Again - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition off, then start engine. Monitor for DTCs. If same DTC P1622 is present, go to next step. If same DTC P1622 is not present, go to step 4.
3. Check If Engine Starts Normally Using Another Registered Key - Turn ignition off. Check if engine start normally using another registered key. If engine starts normally, key used previously is defective, discard it and go to next step. If engine does not start, go to next step.
4. Verify Troubleshooting Of DTC P1603 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1622 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify DTC P1623 Detected Again - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition off, then start engine. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1623 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
3. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 4.
2. Follow Other Detected DTC First - Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition to off, then to START position. Monitor for DTCs. If DTC P1602 is not present, go to next step. If DTC P1602 is present, see «DTC P1602: IMMOBILIZER UNIT-PCM COMMUNICATION LINE ERROR»(ref-151884-S33454000732003010900000).
3. Inspect Immobilizer Unit Connector For Poor Connection - Monitor for DTC P1621 being stored in PCM memory. If DTC P1621 is not present, go to next step. If DTC P1621 is present, see «DTC P1621: CODE WORD MISMATCH AFTER ENGINE CRANKING»(ref-151884-S07952219822003010900000).
4. Verify Troubleshooting Of DTC P1624 Completed - Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Turn ignition off, then start engine. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1624 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 9. If repair information is not available, go to next step.
2. Inspect Drive Belt Condition - Turn ignition off. Inspect drive belts for condition and proper tension. For drive belt tension specification, see appropriate BELT ADJUSTMENT under SPECIFICATIONS in COOLING SYSTEM SPECIFICATIONS & DRIVE BELT ROUTING article in ENGINE COOLING. If drivebelts are okay, go to next step. If drive belt is faulty, adjust or replace as necessary. After repair, go to step 9.
3. Inspect PCM Connector For Poor Connection - Disconnect PCM 24-pin harness connector. (Scheme 41) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 9.
4. Inspect Generator Connector For Poor Connection - Disconnect generator 2-pin harness connector. (Scheme 41) Check for poor connection at generator connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 9.
5. Inspect Generator Control Circuit For Short To GND - Check continuity between ground and generator 2-pin harness connector terminal "D" (Gray/Red wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Gray/Red wire between generator harness connector terminal "D" and PCM 24-pin harness connector terminal "3M". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
6. Inspect Generator Output Voltage Monitor Circuit For GND - Check continuity between ground and generator 2-pin harness connector terminal "P" (Gray wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Gray wire between generator harness connector terminal "P" and PCM 31-pin harness connector terminal "4T". After repair, go to step 9.
7. Inspect Generator Control Circuit For Open Circuit - Check continuity between generator 2-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3M" (Gray/Red wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray/Red wire between generator harness connector terminal "D" and PCM 24-pin harness connector terminal "3M". After repair, go to step 9.
8. Inspect Generator Output Voltage Monitor Circuit For Open Circuit - Check continuity between generator 2-pin harness connector terminal "P" and PCM 31-pin harness connector terminal "4T" (Gray wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray wire between generator harness connector terminal "P" and PCM 31-pin harness connector terminal "4T". After repair, go to next step.
9. Verify Troubleshooting Of DTC P1631 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1631 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

Scheme 41

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 7.
2. Inspect Generator Connector For Poor Connection - Turn ignition off. Disconnect generator 2-pin harness connector. (Scheme 41) Check for poor connection at generator connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 7.
3. Determine If Generator Malfunction Or Other Malfunction - Turn ignition on, engine off. Measure voltage between ground and generator 2-pin harness connector terminal "D" (Gray/Red wire). If battery voltage is present, go to next step. If battery voltageis not present, possible malfunction at generator. Go to step 6.
4. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 24-pin harness connector. (Scheme 41) Check for poor connection at PCM connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 7.
5. Inspect Generator Control Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between ground and generator 2-pin harness connector terminal "D" (Gray/Red wire). If battery voltage is present, repair short circuit to battery voltage in Gray/Red wire between generator harness connector terminal "D" and PCM 24-pin harness connector terminal "3M". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair go to step 7. If battery voltage is not found, go to step 7.
6. Inspect Generator Control Terminal For Short To Power - Measure voltage between ground and generator connector terminal "D" component side. If battery voltage is not present, go to next step. If battery voltage is present, repair or replace generator (internal failure). After repair, go to next step.
7. Verify Troubleshooting Of DTC P1633 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1631 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 6.
2. Inspect Battery - Turn ignition off. Perform battery inspection. If battery is okay, go to next step. If battery is faulty, replace battery. After repair, go to step 6.
3. Inspect Generator Terminal For Poor Installation - Check generator harness connector terminal "B" (White wire) for loose nut. (Scheme 41) If generator terminal installation nut is tight, go to next step. If generator terminal installation nut is loose, retighten installation nut. After repair, go to step 6.
4. Inspect Poor Installation Of Battery Positive Terminal - Check for looseness of positive battery terminal. If positive battery terminal is tight, go to next step. If positive battery terminal is loose, reinstall battery terminal correctly on post and tighten clamping bolt. After repair, go to step 6.
5. Inspect Battery Charging Circuit - Start engine and let it idle. Disconnect positive battery terminal while engine is running. If engine does not stall, go to next step. If engine stalls, repair or replace open circuit in White wire between generator harness connector terminal and positive battery terminal. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
6. Verify Troubleshooting Of DTC P1634 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P1634 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Inspect VTCS Vacuum Switch Connector For Poor Connection - Turn ignition off. Disconnect VTCS vacuum switch 2-pin harness connector. Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 9.
3. Inspect VTCS Vacuum Switch GND Circuit For Open - Turn ignition off. Measure continuity between ground and VTCS vacuum switch harness connector terminal "B" (Black wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between VTCS vacuum switch harness connector terminal "B" and body ground joint connector "JC-02". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 9.
4. Inspect VTCS Vacuum Switch For Being Stuck Open - Inspect VTCS vacuum switch. See «VARIABLE TUMBLE CONTROL SYSTEM - MIATA, PROTEGE & PROTEGE5»(ref-151892-S26634118082003010900000) under AIR INDUCTION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VTCS vacuum switch is okay, go to next step. If VTCS vacuum switch is faulty, replace VTCS vacuum switch. After repair, go to step 9.
5. Inspect VTCS Solenoid Valve For Being Stuck Open - Inspect VTCS solenoid valve. See «VARIABLE TUMBLE CONTROL SYSTEM - MIATA, PROTEGE & PROTEGE5»(ref-151892-S26634118082003010900000) under AIR INDUCTION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VTCS solenoid valve is okay, go to next step. If VTCS solenoid valve is faulty. Replace VTCS solenoid valve. After repair, go to step 9.
6. Inspect Vacuum Lines For Leakage - Inspect vacuum line. See «VACUUM DIAGRAMS»(ref-151899) article. If vacuum lines are okay, go to step 9. If any vacuum lines are leaking, replace leaking vacuum line(s). After repair, go to step 9.
7. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. see scheme 3 Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 9.
8. Inspect VTCS Vacuum Switch Signal Circuit For Short To Power - Turn ignition off, then on (engine off). Measure voltage between ground and PCM 31-pin harness connector terminal "4J" (Orange wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Orange wire between VTCS vacuum switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4J". After repair, go to next step.
9. Verify Troubleshooting Of DTC P2004 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2004 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Inspect VTCS Vacuum Switch Connector For Poor Connection - Turn ignition off. Disconnect VTCS vacuum switch harness connector. Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 8.
3. Inspect VTCS Vacuum Switch For Being Stuck Close - Inspect VTCS vacuum switch. See «VARIABLE TUMBLE CONTROL SYSTEM - MIATA, PROTEGE & PROTEGE5»(ref-151892-S26634118082003010900000) under AIR INDUCTION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VTCS vacuum switch is okay, go to next step. If VTCS vacuum switch is faulty, replace VTCS vacuum switch. After repair, go to step 8.
4. Inspect VTCS Solenoid Valve For Being Stuck Close - Inspect VTCS solenoid valve. See «VARIABLE TUMBLE CONTROL SYSTEM - MIATA, PROTEGE & PROTEGE5»(ref-151892-S26634118082003010900000) under AIR INDUCTION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VTCS solenoid valve is okay, go to next step. If VTCS solenoid valve is faulty. Replace VTCS solenoid valve. After repair, go to step 8.
5. Inspect Vacuum Lines For Misconnection - Inspect vacuum line. See «VACUUM DIAGRAMS»(ref-151899) article. If vacuum lines are okay, go to step 8. If any vacuum lines are leaking, replace leaking vacuum line(s). After repair, go to step 8.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. see scheme 3 Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 8.
7. Inspect VTCS Vacuum Switch Signal Circuit For Short To GND - Turn ignition off. Check continuity between ground and PCM 31-pin harness connector terminal "4J" (Orange wire). If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Orange wire between VTCS vacuum switch harness connector terminal "A" and PCM 31-pin harness connector terminal "4J". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
8. Verify Troubleshooting Of DTC P2006 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2006 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Determine If Intermittent Concern Or Continuous Concern - Leave ignition on. Using scan tool. Monitor for DTCs. If DTC P2009 is present again, go to next step. If DTC is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Determine If Open Circuit Or Short To Ground Malfunction - Disconnect VTCS solenoid valve tube that connects to intake manifold. Connect vacuum pump to VTCS solenoid valve. Apply vacuum and wait 5 seconds. If vacuum is not maintained, go to next step. If vacuum is maintained, got to step 5.
4. Inspect VTCS Solenoid Valve For Passage Control - Turn ignition off. Disconnect VTCS solenoid valve 2-pin harness connector. Apply vacuum to VTCS solenoid valve. If vacuum is maintained, repair short to ground in Black/White wire between VTCS solenoid valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2N". see scheme 3 See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10. If vacuum is not maintained, replace VTCS solenoid valve. After repair, go to step 10.
5. Inspect VTCS Solenoid Valve Connector For Poor Connection - Turn ignition off. Disconnect VTCS solenoid valve 2-pin harness connector. Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 10.
6. Inspect VTCS Solenoid Valve - Measure resistance between VTCS solenoid valve terminals. If resistance reading is more than 28 ohms, go to next step. If resistance reading is not as specified, replace VTCS solenoid valve. After repair, go to step 10.
7. Inspect VTCS Solenoid Valve Power Supply Circuit For Open Circuit - Disconnect VTCS solenoid valve 2-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and VTCS solenoid valve harness connector terminal "A" (White/Red wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White/Red wire between VTCS solenoid valve harness connector terminal "A" and main relay 4-pin harness connector terminal "D". After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 10.
9. Inspect VTCS Solenoid Valve Control Circuit For Open Circuit - Reconnect VTCS solenoid valve 2-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and PCM 17-pin harness connector terminal "2N" (Black/White wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Black/White wire between VTCS solenoid valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2N". After repair, go to next step.
10. Verify Troubleshooting Of DTC P2009 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2009 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Determine If Intermittent Concern Or Continuous Concern - Leave ignition on. Using scan tool. Monitor for DTCs. If DTC P2010 is present again, go to next step. If DTC is not present, problem is intermittent. See «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLESHOOTING - NO CODES article.
3. Determine If Open Circuit Or Short To Ground Malfunction - Disconnect VTCS solenoid valve vacuum hose that connects to intake manifold. Connect vacuum pump to VTCS solenoid valve. Apply vacuum and wait 5 seconds. If vacuum is not maintained, go to next step. If vacuum is maintained, go to step 5.
4. Inspect VTCS Solenoid Valve For Passage Control - Turn ignition off. Disconnect VTCS solenoid valve 2-pin harness connector. Apply vacuum to VTCS solenoid valve and wait 5 seconds. If vacuum is maintained, repair short circuit to ground in Black/White wire between VTCS solenoid valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2N". see scheme 3 See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10. If vacuum is not maintained, replace VTCS solenoid valve. After repair, go to step 10.
5. Inspect VTCS Solenoid Valve Connector For Poor Connection - Turn ignition off. Disconnect VTCS solenoid valve 2-pin harness connector. Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 10.
6. Inspect VTCS Solenoid Valve - Measure resistance between VTCS solenoid valve terminals. If resistance reading is more than 28 ohms, go to next step. If resistance reading is not as specified, replace VTCS solenoid valve. After repair, go to step 10.
7. Inspect VTCS Solenoid Valve Power Supply Circuit For Open Circuit - Disconnect VTCS solenoid valve 2-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and VTCS solenoid valve harness connector terminal "A" (White/Red wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White/Red wire between VTCS solenoid valve harness connector terminal "A" and main relay 4-pin harness connector terminal "D". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 31-pin harness connector. see scheme 3 Check for poor connection at VTCS connector terminals due to damaged, pulled-out pins, corrosion, etc. If connector terminals are okay, go to next step. If connector terminals are faulty, repair or replace as necessary. After repair, go to step 10.
9. Inspect VTCS Solenoid Valve Control Circuit For Short To Power - Disconnect VTCS solenoid valve 2-pin harness connector. Turn ignition on, engine off. Measure voltage between ground and PCM 17-pin harness connector terminal "2N". If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Black/White wire between VTCS solenoid valve harness connector terminal "B" and PCM 17-pin harness connector terminal "2N". After repair, go to next step.
10. Verify Troubleshooting Of DTC P2010 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2010 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify Related Pending Code Or Stored DTCs - Turn ignition off, then on (engine off). Verify related Pending Code or stored DTCs. If DTC P2406 is not present with P2402, go to next step. If DTC P2406 is present with P2402, go to «DTC P2406: EVAP SYSTEM LEAK DETECTION PUMP ORIFICE CLOGGING»(ref-151884-S40224160132003022500000).
3. Check EVAP System Leak Detection Pump Circuit For Short To Power - Turn ignition on. Disconnect EVAP system leak detection pump 4-pin harness connector. see scheme 36 Measure voltage between ground and EVAP system leak detection pump 4-pin harness connector terminal "D" (Yellow/Black wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Yellow/Black wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 24-pin harness connector terminal "3K". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
4. Verify Troubleshooting Of DTC P2402 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2402 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Check EVAP Hose Bending - Inspect EVAP hose for bending. If EVAP hose is okay, go to next step. If EVAP hose is bent, replace faulty EVAP hose. After repair, go to step 4.
3. Check Air Filter For Clogging - Inspect air filter for clogging. If air filter is okay, go to next step. If air filter is clogged, replace air filter. After repair, go to next step.
4. Verify Troubleshooting Of DTC P2404 Completed - Return vehicle to original condition. Connect scan tool to DLC-2. (Scheme 13) Clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Monitor for DTCs. If same DTC is not present, go to next step. If same DTC P2404 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
5. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, replace EVAP system leak detection pump. After repair, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify Troubleshooting Of DTC P2405 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Perform DRIVE MODE 4. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P2405 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
3. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, replace EVAP system leak detection pump. After repair, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Verify Troubleshooting Of DTC P2406 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Perform DRIVE MODE 4. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P2406 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
3. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. (Scheme 13) Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to next step.
2. Inspect EVAP System Leak Detection Pump Heater - See «FUEL EVAPORATIVE SYSTEM (MIATA & MPV)»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EVAP system leak detection pump is okay, go to next step. If EVAP system leak detection pump is faulty, replace EVAP system leak detection pump. After repair, go to next step.
3. Verify Troubleshooting Of DTC P2407 Completed - Return vehicle to original condition. Turn ignition on, engine off. Using scan tool, clear DTCs from PCM memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151884-S38555540052003010900000) under SELF-DIAGNOSTIC SYSTEM. Start engine and let idle until normal operating temperature is reached. Perform DRIVE MODE 4. See «DRIVE MODES»(ref-151884-S01000799312003010900000) under SELF-DIAGNOSTIC SYSTEM. Monitor for pending DTCs. If same DTC is not present, go to next step. If same DTC P2407 is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step.
4. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151884-S39899430132003022600000). If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.

1. Disconnect appropriate sensor connector where reference voltage problem is suspected. Turn ignition on, engine off. Check voltage between harness connector reference voltage terminal and ground terminal. If reference voltage is 6 volts or less, go to next step. If reference voltage is more than 6 volts, go to step 14.
2. Turn ignition on, engine off. Measure voltage across battery terminals. If battery voltage is more than 10.5 volts, go to next step. If battery voltage is not as specified, inspect charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
3. Turn ignition off. Disconnect sensor harness connector where reference voltage circuit check failed. Turn ignition on, engine off. Measure voltage between positive battery terminal and appropriate sensor harness connector ground circuit terminal (Black/Red wire). Voltage should be more than 10.5 volts and within one volt of battery voltage. If voltage reading is as specified, go to next step. If voltage reading is not as specified, go to step 9. NOTE: Purpose of following step is to determine if scan tool is communicating with PCM.
4. Turn ignition on, engine off. Using scan tool, attempt to access ECT PID. If ECT PID cannot be accessed, go to next step. If ECT PID can be accessed, go to step 8.
5. Turn ignition off. Disconnect TP sensor and EGR boost sensor 3-pin harness connectors. (Scheme 42) Turn ignition on, engine off. Measure voltage between TP sensor harness connector terminal "A" (Light Green/Red wire) and terminal "B" (Black/Red wire). If voltage reading is not 4.0-6.0 volts, go to next step. If voltage reading is 4.0-6.0 volts, replace EGR boost sensor.
6. Turn ignition off. Disconnect PCM 31-pin harness connector. (Scheme 42) Turn ignition on, engine off. Measure voltage between PCM 31-pin harness connector terminal "4AF" (White/Red wire) and terminal "4O" (Black/Red wire). If voltage reading is more than 10.5 volts, go to next step. If voltage reading is not as specified, repair open circuit in White/Red wire between main relay 4-pin harness connector terminal "D" and PCM 31-pin harness connector terminal "4AF". See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.
7. Turn ignition off. Leave TP sensor, EGR boost sensor and PCM harness connectors disconnected. Disconnect scan tool from DLC-2. Measure resistance between PCM harness connector terminal "4L" (Light Green/Red wire) and terminal "4O" (Black/Red wire). Resistance should be more than 10,000 ohms. If resistance is not as specified, repair short circuit to ground in Light Green/Red wire between TP sensor, EGR boost sensor and PCM harness connectors. If resistance is as specified, return vehicle to original condition. Turn ignition on and recheck reference voltage at suspect sensor 3-pin harness connector. If reference voltage is still not 4.5-5.5 volts, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article.
8. Turn ignition off. Leave sensor harness connector disconnected where reference voltage circuit failed. Disconnect PCM 31-pin harness connector. (Scheme 42) Measure resistance between PCM 31-pin harness connector terminal "4L" and reference voltage circuit at appropriate sensor connector terminal (Light Green/Red wire). If resistance is not less than 5 ohms, repair open circuit in Light Green/Red wire between suspect sensor harness connector and PCM 31-pin harness connector terminal "4L". If resistance is less than 5 ohms, return vehicle to original condition. Turn ignition on and recheck reference voltage at suspect sensor connector. If reference voltage is still not 4.5-5.5 volts, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. NOTE: Purpose of following step is to determine if scan tool is communicating with PCM.
9. Turn ignition off. Connect scan tool to DLC-2. Turn ignition on, engine off. Using scan tool, attempt to access ECT PID. If ECT PID cannot be accessed, go to next step. If ECT PID can be accessed, go to step 12.
10. Verify if DTCs are present for two or more of following sensors connected to PCM 31-pin harness connector terminal "4O" (Black/Red wire). IAT sensor. Front HO2S. ECT sensor. TP sensor. EGR boost sensor. Rear HO2S. If two or more DTCs related to above sensors are present, go to next step. If no DTCs related to above sensorsare present, repair open circuit in Black/Red wire between sensor harness connector where reference voltage circuit failed and PCM 31-pin harness connector terminal "4O".
11. Turn ignition off. Leave sensor harness connector where faulty reference voltage circuit was found disconnected. Leave PCM 31-pin harness connector disconnected. Disconnect scan tool from DLC-2. Measure resistance between PCM 31-pin harness connector terminal "4O" and appropriate sensor harness connector terminal (Black/Red wire). If resistance is less than 5 ohms, reconnect sensor harness connector and go to next step. If resistance is not as specified, repair open circuit in Black/Red wire between suspect sensor harness connector and PCM 31-pin harness connector terminal "4O".
12. Turn ignition off. Disconnect scan tool from DLC-2. Disconnect PCM 24-pin harness connector. Measure resistance between negative battery terminal and PCM 24-pin harness connector terminal "3A" (Black wire) and terminal "3B" (Black/Red wire). (Scheme 42) If resistance readings are less than 5 ohms, reconnect PCM 24-pin harness connector and go to next step. If any resistance readings are not less than 5 ohms, repair open circuit in either Black or Black/Red wire between ground and PCM 24-pin harness connector.
13. Turn ignition off. Measure resistance between ground and following sensor harness connector ground circuit terminals (Black/Red wire): IAT sensor. Front HO2S. ECT sensor. TP sensor. EGR boost sensor. Rear HO2S. If each sensor resistance reading is less than 5 ohms, go to next step. If any sensor resistance reading is not less than 5 ohms, recheck reference voltage at suspect sensor harness connector. If reference voltage is still not 4.5-5.5 volts, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article.
14. Ensure harness connectors are disconnected at sensor where reference voltage circuit failed and PCM. Disconnect TP sensor and EGR boost sensor harness connectors. (Scheme 42) Turn ignition on, engine off. Measure voltage between negative battery terminal and TP sensor 3-pin harness connector terminal "A" (Light Green/Red wire). If voltage reading is less than 5 volts, return vehicle to original condition. Recheck reference voltage at suspect sensor harness connector. If reference voltage is still not 4.5-5.5 volts, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. If voltage reading is not as specified, repair short circuit to power in Light Green/Red wire between disconnected sensor 3-pin harness connector and PCM 31-pin harness connector terminal "4L".

Scheme 42