DIAGNOSTIC TROUBLE CODES (DTC)
Powertrain Control Module (PCM) is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, PCM will illuminate Malfunction Indicator Light (MIL) located on instrument cluster. When a malfunction is detected and MIL is turned on, a corresponding DTC will be stored in PCM memory. Each DTC is directly related to a specific CIRCUIT TEST.
DIAGNOSTIC PROCEDURE
Diagnosis of computerized engine control system should be performed in the following order
- Ensure all engine systems not related to computer are operating properly. DO NOT proceed with testing unless all other problems have been repaired. Perform «MALFUNCTION INDICATOR LIGHT (MIL) CHECK»(ref-26219-S07538856302001010500000) before using CIRCUIT TESTS.
- Check for any Technical Service Bulletins (TSBs) that may apply. Retrieve any DTCs that may be present. If DTCs were displayed, follow procedures in appropriate CIRCUIT TEST.
- If DTCs were not displayed, and a driveability problem or intermittent problem exists, go to «TESTS W/O CODES»(ref-26207) article.
Note. ALWAYS clear DTCs, confirm closed loop operation, and test drive vehicle after repairs are made. Ensure MIL does NOT illuminate.
SPECIAL TOOLS (DIAGNOSTIC)
Note. In this article, diagnosis of the computerized engine control system is based on using a scan tool. Use of a scan tool saves a great deal of diagnostic time and prevents replacement of good parts. Any computer related diagnosis without a scan tool is NOT recommended.
Computerized engine control system is diagnosed using a Tech 1 or other OBD-II compatible scan tool. However, other tools are needed to aid in diagnosing problems. These tools include a tachometer (inductive pick-up), a non-powered test light, digital multimeter with 10-megohm input impedance (minimum), vacuum pump and vacuum gauge, High Energy Ignition (HEI) spark tester, fuel pressure gauge, fuel injector test light (noid-light), and fused jumper wires. A test light, rather than a voltmeter, must be used when indicated by a CIRCUIT TEST procedure.
SCAN TOOL USAGE
Note. Before connecting scan tool, follow steps in MALFUNCTION INDICATOR LIGHT (MIL) CHECK.
Scan tool is a specialized tester which can diagnose on-board computer control systems by providing almost instant access to circuit data without crawling under dash or hood to backprobe sensors and connectors. Scan tools reduce diagnostic time by furnishing input data (sensor values) which can be compared to specification parameters.
Scan tools also furnish status data of output devices (solenoids and motors). However, status parameters are only an indication that output signals have been sent to devices by PCM. They do not indicate whether devices respond properly to that signal. This must be verified at output device using a voltmeter or test light.
If DTCs are not present, a problem may still exist. Driveability-related problems with DTCs displayed occur about 20 percent of the time, while driveability problems without DTCs occur about 80 percent of the time. Out-of-calibration sensors may NOT set a DTC, but WILL cause driveability problems. A scan tool is the easiest method of checking sensor specifications and other data parameters. A scan tool is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters.
Note. Information obtained by a scan tool is only as accurate as the scan tool itself. A scan tool that displays faulty data should not be used. If faulty data readings are suspected, verify scan tool information using a digital multimeter and wiring schematic.
DIAGNOSTIC TROUBLE CODE (DTC) DEFINITION
| DTC | System Affected | Condition |
|---|---|---|
| P0101 | MAF Sensor Circuit | Poor MAF Sensor Performance |
| P0102 | MAF Sensor Circuit | MAF Sensor Low Input |
| P0103 | MAF Sensor Circuit | MAF Sensor High Input |
| P0112 | IAT Sensor Circuit | Low IAT Sensor Circuit Input |
| P0113 | IAT Sensor Circuit | High IAT Sensor Circuit Input |
| P0117 | ECT Sensor Circuit | Low ECT Sensor Circuit Input |
| P0118 | ECT Sensor Circuit | High ECT Sensor Circuit Input |
| P0121 | TP Sensor Circuit | Poor TP Sensor Performance |
| P0122 | TP Sensor Circuit | Low TP Sensor Circuit Input |
| P0123 | TP Sensor Circuit | High TP Sensor Circuit Input |
| P0125 | ECT Sensor Circuit | Insufficient Coolant Temperature For Closed Loop Operation |
| P0131 | HO2S No. 1 Circuit | Low HO2S No. 1 Circuit Input |
| P0132 | HO2S No. 1 Circuit | High HO2S No. 1 Circuit Input |
| P0133 | HO2S No. 1 Circuit | Slow Response Of HO2S No. 1 Circuit |
| P0134 | HO2S No. 1 Circuit | No HO2S No. 1 Circuit Activity Detected |
| P0135 | HO2S No. 1 Heater Circuit HO2S | No. 1 Heater Circuit Malfunction |
| P0136 | HO2S No. 2 Circuit | HO2S No. 2 Circuit Malfunction |
| P0141 | HO2S No. 2 Heater Circuit | HO2S No. 2 Heater Circuit Malfunction |
| P0171 | Fuel System Lean | Total Fuel Trim Is Greater Than Allowed Specification |
| P0172 | Fuel System Rich | Total Fuel Trim Is Less Than Allowed Specification |
| P0300 | Random Misfire Detected | Electrical Or Mechanical Misfire (Catalyst Damaging) |
| P0301 | Cylinder No. 1 Misfire | Electrical Or Mechanical Misfire Common To One Cylinder |
| P0302 | Cylinder No. 2 Misfire | Electrical Or Mechanical Misfire Common To One Cylinder |
| P0303 | Cylinder No. 3 Misfire | Electrical Or Mechanical Misfire Common To One Cylinder |
| P0304 | Cylinder No. 4 Misfire | Electrical Or Mechanical Misfire Common To One Cylinder |
| P0335 | CKP Sensor Circuit | No CKP Sensor Signal (Engine Running) |
| P0340 | CMP Sensor Circuit | No CMP Sensor Signal For 2 Seconds During Engine Cranking |
| P0400 | EGR Flow Malfunction | Excessive Or Insufficient EGR Flow |
| P0420 | Catalyst Efficiency Low | HO2S No. 1 & 2 Output Is Similar |
| P0440 (1) | EVAP Emission Control System | EVAP System Leak Detected |
| P0443 (2) | Canister Purge Control Valve Circuit | Canister Purge Control System Malfunction |
| P0450 (1) | EVAP System Pressure Sensor | Pressure Sensor Circuit Open Or Shorted To Ground |
| P0461 | Fuel Level Sensor Circuit | Poor Fuel Level Sensor Circuit Performance |
| P0463 | Fuel Level Sensor Circuit | High Voltage Input |
| P0500 | Vehicle Speed Sensor Malfunction | No Signal In "D" Range |
| P0505 | Idle Control System Malfunction | Target Idle Speed Not Obtained |
| P0510 | CTP Switch Malfunction | No CTP Switch Activity |
| P0601 | PCM Memory Check Sum Error | Data Write Error |
| P0603 | PCM Keep Alive Memory Error | EEPROM Memory Error |
| P1408 | MDP Sensor Circuit | MDP Sensor Circuit Open Or Shorted To Ground |
| P1410 (1) | Fuel Tank Pressure Control System | Low Voltage Signal With High Fuel Level Reading |
| P1450 | Barometric Pressure Sensor | Low Or High Input |
| P1451 | Barometric Pressure Sensor | Barometric Pressure Sensor Performance Problem During Cranking |
| P1500 | Engine Starter Signal Circuit | No Input Or Constant Input From Starter Signal Circuit |
| P1510 | PCM Back-Up Power Supply Malfunction | No Back-Up Power Supply After Engine Start |
| P1530 | Ignition Timing Adjustment Switch Circuit | Test Switch Terminal Shorted To Ground |
| P1715 (3) | PNP Switch Circuit | Engine Start Or High Speed Is Detected In Other Than "P" Or "N" Range |
| (1) Applies only to vehicles equipped with tank pressure control solenoid vacuum valve. (2) Applies only to vehicles not equipped with tank pressure control solenoid vacuum valve. (3) Applies only to vehicles equipped with 3-speed A/T. | ||
| (1) | Applies only to vehicles equipped with tank pressure control solenoid vacuum valve. |
| (2) | Applies only to vehicles not equipped with tank pressure control solenoid vacuum valve. |
| (3) | Applies only to vehicles equipped with 3-speed A/T. |
DTC IDENTIFICATION
TEST A-1: MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE
When ignition is on, PCM energizes main relay. As PCM is supplied with ignition power, MIL turns on. After engine starts, MIL will turn off if no malfunction is detected. If a malfunction is detected, MIL will remain on until system is repaired.
- Turn ignition on. Observe instrument cluster warning lights. If all warning lights come on except MIL, go to next step. If no warning lights come on, check for blown fuses, faulty ignition switch, or poor connection at instrument cluster. Repair as necessary.
- Attempt to start engine. If engine does not start, go to «CIRCUIT TEST A-3»(ref-26219-S14199975812001010500000). If engine starts, turn ignition off and disconnect PCM connectors. On models with 3-speed automatic or manual transmission, connect a fused jumper wire between PCM harness connector "C", terminal No. 14 (Purple/Yellow wire) to ground. On models with 4-speed automatic transmission, connect fused jumper wire between PCM harness connector "A", terminal No. 23 (Purple/Yellow wire) to ground. Turn ignition on. If MIL comes on, replace PCM. If MIL does not come on, repair open Purple/Yellow wire or replace faulty MIL bulb. Retest system.
TEST A-2: MALFUNCTION INDICATOR LIGHT (MIL) REMAINS ON
When ignition is on, PCM energizes main relay. As PCM is supplied with ignition power, MIL turns on. After engine starts, MIL will turn off if no malfunction is detected. If a malfunction is detected, MIL will remain on until system is repaired.
- Connect scan tool to Data Link Connector (DLC). Attempt to retrieve DTCs with ignition on, engine off. If any DTCs are displayed, see appropriate DTC. If no DTCs are displayed, go to next step.
- Attempt to retrieve DTCs with engine running. If no DTCs are displayed, turn ignition off. Disconnect PCM connectors. Turn ignition on. If MIL comes on, repair Purple/Yellow wire between MIL bulb and PCM harness for short to ground. If MIL does not come on, replace PCM. Retest system.
Scheme 7
Scheme 8
- Observe main relay behind center of instrument panel while ignition switch is cycled from ON to OFF position. If no sound is heard, go to next step. If sound is heard at relay, turn ignition off. Disconnect PCM harness connectors and go to step 5).
- Turn ignition off. Remove main relay. Using an ohmmeter, measure resistance between relay terminals No. 1 and 3. (Scheme 7)or (Scheme 8). On models produced in Japan, resistance should be 61-72 ohms. On models produced in Canada, resistance should be 79-95 ohms. Nation of manufacture is indicated by first 3 digits of VIN code. Infinite resistance should exist between relay terminals No. 2 and 4. Apply battery voltage to terminals No. 1 and 3. Ensure continuity exists between terminals No. 2 and 4. Replace relay if continuity is not as specified. If relay is okay, go to next step.
- Ensure 15-amp FI fuse in engine compartment relay/fuse box is okay. If fuse is blown, check for short circuit and repair as necessary. If fuse is okay, go to next step.
- Turn ignition off. Disconnect PCM harness connectors. Reinstall main relay. Turn ignition on. On models with 3-speed automatic or manual transmission, measure voltage between ground and PCM harness connector "C", terminal No. 10 (Blue wire). On models with 4-speed automatic transmission, measure voltage between ground and PCM harness connector "A", terminal No. 1 (Blue wire). If reading is 10-14 volts, go to next step. If reading is not as specified, repair open Black/Red wire between 15-amp FI fuse and main relay, or open Blue wire between main relay and PCM. Retest system.
- On models with 3-speed automatic or manual transmission, connect a fused jumper wire between PCM harness connector "C", terminal No. 10 (Blue wire) and ground. On models with 4-speed automatic transmission, connect a fused jumper wire between PCM harness connector "A", terminal No. 1 (Blue wire) and ground. Turn ignition on. On models with 3-speed automatic or manual transmission, measure voltage between ground and PCM harness connector "C", terminals No. 12 and 13 (Blue/Black wires). On models with 4-speed automatic transmission, measure voltage between ground and PCM harness connector "A", terminals No. 3 and 16 (Blue/Black wires). If reading is 10-14 volts, go to next step. If reading is not as specified, repair open Black/Red wire between 15-amp FI fuse and main relay, or open Black/Blue wire between PCM and main relay. Retest system.
- Check for open Black/Green, Black/Blue or Black/Orange wires (PCM ground wires). Repair as necessary. If wires are okay, replace PCM. Retest system.
See also:
• PIN VOLTAGE CHARTS
• WIRING DIAGRAMS