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Engine Controls - Self-Diagnostics: Other Honda Civic GA

Testing & Diagnostics 5 illustrations ~12502 words

Malfunction Indicator Light (MIL) Never Comes On, Even For 2 Seconds, After Ignition Is Turned On (D16Y5 M/T)

  1. If symptom is intermittent, check for: Loose No. 25 METER (7.5-amp) fuse located in underdash fuse/relay box. Poor connection at PCM 32-pin connector "A" terminal No. 18. see scheme 1 Intermittent open in Green/Orange wire between PCM 32-pin connector "A" terminal No. 18 and gauge assembly. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. Perform repairs as necessary and recheck MIL operation. If no problems are found, go to next step.
  2. Turn ignition on. If low oil pressure light is on, go to next step. If lower oil pressure light is not on, replace No. 25 METER (7.5-amp) fuse. Check for short or open in Yellow wire between No. 25 METER (7.5-amp) fuse and gauge assembly. See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Try to start engine. If engine starts, go to next step. If engine does not start, turn ignition on. Using backprobe set, measure voltage between ground and PCM 32-pin connector "A" terminal No 10 (Black wire) and terminal No. 23 (Black wire), individually. see scheme 1 If one volt or more exists, check for open in suspect Black wire between PCM and ground connection, located at thermostat housing. If less than one volt exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  4. Turn ignition off. Using backprobe set, connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 18 (Green/Orange wire). see scheme 1 Turn ignition on. If MIL comes on, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If MIL does not come on, replace MIL bulb and/or check for open in Green/Orange wire between PCM 32-pin connector "A" and gauge assembly. See appropriate wiring diagram in WIRING DIAGRAMS article.

Malfunction Indicator Light (MIL) Never Comes On, Even For 2 Seconds, After Ignition Is Turned On (Except D16Y5 M/T)

  1. If symptom is intermittent, check for: Loose No. 25 METER (7.5-amp) fuse located in underdash fuse/relay box. Loose No. 44 FI E/M (15-amp) fuse located in underhood fuse/relay box. Loose No. 13 FUEL PUMP (15-amp) fuse located in underdash fuse/relay box. Intermittent short in Yellow/Red wire between PCM 31-pin connector "C" terminal No. 19 and MAP sensor. see scheme 3 See appropriate wiring diagram in WIRING DIAGRAMS article. Intermittent short in Yellow/Blue wire between PCM 31-pin connector "C" terminal No. 28, TP sensor, EGR valve lift sensor (if equipped) and/or fuel tank pressure sensor. Faulty PGM-FI main relay. Perform repairs as necessary and recheck MIL operation. If no problems are found, go to next step.
  2. Turn ignition on. If low oil pressure light is on, go to next step. If low oil pressure light is not on, replace No. 25 METER (7.5-amp) fuse. Check for short or open in Yellow wire between No. 25 METER (7.5-amp) fuse and gauge assembly. See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Try to start engine. If engine does not start, go to step 5. If engine starts, go to next step.
  4. Turn ignition off. Using backprobe set, connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 18 (Green/Orange wire). see scheme 1 Turn ignition on. If MIL comes on, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If MIL does not come on, replace MIL bulb and/or check for open in Green/Orange wire between PCM 32-pin connector "A" and gauge assembly. See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Turn ignition off. Check No. 44 FI E/M (15-amp) fuse located in underhood fuse/relay box. If fuse is okay, go to next step. If fuse is blown, check for short in White/Black wire between No. 44 FI E/M (15-amp) fuse and PGM-FI main relay. Replace No. 44 FI E/M (15-amp) fuse.
  6. Check No. 13 FUEL PUMP (15-amp) fuse located in underdash fuse/relay box. If fuse is okay, go to next step. If fuse is blown, check for short in Yellow/Green wire between No. 13 FUEL PUMP (15-amp) fuse and PGM-FI main relay. Replace No. 13 FUEL PUMP (15-amp) fuse.
  7. Disconnect fuel injector connectors and IAC valve connector. Turn ignition on. Using backprobe set, measure voltage between ground and PCM 25-pin connector "B" terminal No. 1 (Yellow/Black wire) and terminal No. 9 (Yellow/Black wire), individually. If battery voltage exists, go to next step. If battery voltage does not exist, check for open in suspect wire between PCM 25-pin connector "B" and PGM-FI main relay. see scheme 2 If wires are okay, check for poor connections or loose wires at PGM-FI main relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If connections and wires are okay, check PGM-FI main relay. See RELAYS under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article.
  8. Reconnect fuel injector connectors and IAC valve connector. Using backprobe set, measure voltage between ground and PCM 25-pin connector "B" terminal No. 2 (Black wire), No. 10 (Black wire), No. 20 (Brown/Black wire) and terminal No. 22 (Brown/Black wire), individually. If less than one volt exists, go to next step. If one volt or more exists, check for open in suspect wire between PCM 25-pin connector "B" and ground connection, located at left side of intake manifold. See appropriate wiring diagram in WIRING DIAGRAMS article.
  9. Using backprobe set, measure voltage between ground and PCM 31-pin connector "C" terminal No. 19 (Yellow/Red wire) and terminal No. 28 (Yellow/Blue wire), individually. see scheme 3 If about 5 volts exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If about 5 volts does not exist, go to next step.
  10. While measuring voltage between ground and PCM 31-pin connector "C" terminal No. 19 (Yellow/Red wire) and terminal No. 28 (Yellow/Blue wire) individually, disconnect 3-pin connector from Manifold Absolute Pressure (MAP) sensor, Throttle Position (TP) sensor, EGR valve lift sensor and Fuel Tank Pressure (FTP) sensor, one at a time. If about 5 volts does not exist, repair short in suspect wire between MAP, TP, EGR valve or FTP sensor and PCM 31-pin connector "C". If about 5 volts exists, replace sensor that caused about 5 volts.

Malfunction Indicator Light (MIL) Stays On Or Comes On After 2 Seconds (D16Y5 M/T)

  1. If symptom is intermittent, check for: Loose No. 44 FI E/M (15-amp) fuse located in underhood fuse/relay box. Loose No. 13 FUEL PUMP (15-amp) fuse located in underdash fuse/relay box. Intermittent short in Brown wire between PCM 31-pin connector "C" terminal No. 7 and service check connector. see scheme 3 See appropriate wiring diagram in WIRING DIAGRAMS article. Intermittent short in Green/Orange wire between PCM 32-pin connector "A" terminal No. 18 and gauge assembly. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. Intermittent short in Yellow/Red wire between PCM 16-pin connector "D" terminal No. 4 and MAP sensor. see scheme 4 See appropriate wiring diagram in WIRING DIAGRAMS article. Intermittent short in Yellow/Blue wire between PCM 16-pin connector "D" terminal No. 10, TP sensor, EGR valve lift sensor (if equipped) and/or fuel tank pressure sensor. Faulty PGM-FI main relay. Perform repairs as necessary and recheck MIL operation. If no problems are found, go to next step.
  2. Connect scan tool to DLC connector. Turn ignition on. Read Diagnostic Trouble Codes (DTCs). See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-3103-S34636795962000041700000) in SELF-DIAGNOSTICS - INTRODUCTION article. If DTCs are present, go to «DIAGNOSTIC TROUBLE CODE IDENTIFICATION»(ref-2658-S26838207492002082800000) table. After identifying DTC, go to appropriate DTC test. If DTCs are not present, go to next step.
  3. Turn ignition off. Connect SCS service connector to service check connector. See SELF-DIAGNOSTICS - INTRODUCTION article. Turn ignition on. Using MIL read DTCs. If DTCs are not present using MIL, go to step. If DTCs are present using MIL, check for open or short in wire between PCM 31-pin connector "C" terminal No. 8 (Light Blue wire) and DLC terminal No. 15 (Blue/Yellow wire). see scheme 3and see scheme 5. If wire is okay, go to «DIAGNOSTIC TROUBLE CODE IDENTIFICATION»(ref-2658-S26838207492002082800000) table.
  4. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step 7.
  5. Turn ignition off. Disconnect SCS service connector. Turn ignition on. Using backprobe set, measure voltage between ground and PCM 31-pin connector "C" terminal No. 7 (Brown wire). see scheme 3 If about 5.0 volts exists, go to next step. If about 5.0 volts does not exist, check for short to ground in Brown wire between PCM 31-pin connector "C" and service check connector. See appropriate wiring diagram in WIRING DIAGRAMS article.
  6. Turn ignition off. Disconnect PCM 32-pin connector "A". Turn ignition on. If MIL is on, check for short to ground in Green/Orange wire between PCM 32-pin connector "A" terminal No. 18 and MIL. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. If MIL is not on, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  7. Inspect No. 44 FI E/M (15-amp) fuse located in underhood fuse/relay box. If fuse is okay, go to next step. If fuse is open, check for short in White/Black wire between fuse and PGM-FI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article. Replace No. 44 FI E/M (15-amp) fuse.
  8. Inspect No. 13 FUEL PUMP (15-amp) fuse, located in underdash fuse/relay box. If fuse is okay, go to next step. If fuse is open, check for short in Yellow/Green wire between fuse and PGM-FI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article. Replace No. 13 FUEL PUMP (15-amp) fuse.
  9. Turn ignition on. While observing MIL, disconnect 3-pin connector from Manifold Absolute Pressure (MAP) sensor, Throttle Position (TP) sensor and EGR valve lift sensor, one at a time. If MIL does not go off, go to next step. If MIL goes off, replace sensor that caused MIL to go off.
  10. Turn ignition off. Disconnect PCM 16-pin connector "D". Check for continuity between ground and PCM 16-pin connector "D" terminal No. 4 (Yellow/Red wire) and terminal No. 10 (Yellow/Blue wire), individually. see scheme 4 If continuity does not exist, go to next step. If continuity exists, check for short to ground in Yellow/Red wire between PCM 16-pin connector "D" terminal No. 4 and MAP sensor, or Yellow/Blue wire between PCM connector terminal No. 10 and TP sensor and EGR valve lift sensor. See appropriate wiring diagram in WIRING DIAGRAMS article.
  11. Turn ignition off. Disconnect fuel injectors connectors and IAC valve connector. Turn ignition on. Measure voltage between ground and PCM 32-pin connector "A" terminal No. 11 (Yellow/Black wire) and terminal No. 24 (Yellow/Black wire), individually. see scheme 1 If battery voltage exists, go to next step. If battery voltage does not exist, check for open in suspect wire between PCM 32-pin connector "A" and PGM-FI main relay. If wires are okay, check for poor connections or loose wires at PGM-FI main relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If connections and wires are okay, check PGM-FI main relay. See RELAYS under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article.
  12. Turn ignition off and reconnect all sensor connectors. Reconnect PCM 16-pin connector "D". Turn ignition on. Measure voltage between ground and PCM 32-pin connector "A" terminal No. 9 (Brown/Black wire) and terminal No. 22 (Brown/Black wire), individually. If less than one volt exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If one volt or more exists, check for open in suspect wire(s) between PCM 32-pin connector "A" and ground connection, located at thermostat housing. See appropriate wiring diagram in WIRING DIAGRAMS article.

Malfunction Indicator Light (MIL) Stays On Or Comes On After 2 Seconds (Except D16Y5 M/T)

  1. If symptom is intermittent, check for: Intermittent short in Brown wire between PCM 32-pin connector "A" terminal No. 10 and service check connector. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. Intermittent short in Green/Orange wire between PCM 32-pin connector "A" terminal No. 18 and gauge assembly. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. Perform repairs as necessary and recheck MIL operation. If no problems are found, go to next step.
  2. Connect scan tool to DLC connector. Turn ignition on. Read Diagnostic Trouble Codes (DTCs). See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-3103-S34636795962000041700000) in SELF-DIAGNOSTICS - INTRODUCTION article. If DTCs are present, go to «DIAGNOSTIC TROUBLE CODE IDENTIFICATION»(ref-2658-S26838207492002082800000) table. After identifying DTC, go to appropriate DTC test. If DTCs are not present, go to next step.
  3. Turn ignition off. Connect SCS service connector to service check connector. See SELF-DIAGNOSTICS - INTRODUCTION article. Turn ignition on. Using MIL read DTCs. If DTCs are not present using MIL, go to next step. If DTCs are present using MIL, check for open or short in Blue/Yellow wire between PCM 32-pin connector "A" terminal No. 21 and DLC terminal No. 15. see scheme 1and see scheme 5. If wire is okay, recheck for DTCs. Go to «DIAGNOSTIC TROUBLE CODE IDENTIFICATION»(ref-2658-S26838207492002082800000) table. After identifying DTC, go to appropriate DTC test.
  4. Attempt to start engine. If engine starts, go to next step. If engine does not start, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  5. Turn ignition off. Turn ignition on. Using backprobe set, measure voltage between ground and PCM 32-pin connector "A" terminal No. 10 (Brown wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for short to ground in Brown wire between PCM 32-pin connector "A" and service check connector. See appropriate wiring diagram in WIRING DIAGRAMS article.
  6. Turn ignition off. Disconnect PCM 32-pin connector "A". Turn ignition on. If MIL is on, check for short to ground in Green/Orange wire between PCM 32-pin connector "A" terminal No. 18 and MIL. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. If MIL is not on, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

D16Y5 M/T

  1. Turn ignition on. Check MAP sensor using scan tool. If about 30 in. Hg is not indicated, go to next step. If about 30 in. Hg is indicated, problem is intermittent. Check for poor connections or loose wires at MAP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Check MAP sensor using scan tool. If about zero in. Hg is indicated, go to next step. If about zero in. Hg is not indicated, replace MAP sensor.
  3. Turn ignition off and disconnect MAP sensor 3-pin connector. Turn ignition on. Measure voltage between MAP sensor harness connector terminals No. 1 (Yellow/Red wire) and No. 2 (Green/White wire). (Scheme 6) If about 5.0 volts exists, go to next step. If about 5.0 volts does not exist, check for open in Yellow/Red wire between PCM 16-pin connector "D" terminal No. 4 and MAP sensor connector terminal No. 1. see scheme 4 See appropriate wiring diagram in WIRING DIAGRAMS article.
  4. Check MAP sensor using scan tool. If about 0.6 in. Hg or less is not indicated, replace MAP sensor. If about 0.6 in. Hg or less is indicated, go to next step (D16Y5 engine with Continuously Variable Transmission (CVT)), or go to step 5 (except D16Y5 engine with CVT).
  5. On D16Y5 with CVT, turn ignition off. Disconnect 22-pin Transmission Control Module (TCM) connector. TCM is located below left side of instrument panel, behind left kick panel. Turn ignition on. Check MAP sensor using scan tool. If about 0.6 in. Hg or less is indicated, go to next step. If about 0.6 in. Hg or less is not indicated, replace TCM.
  6. On all models, turn ignition off. Disconnect PCM 16-pin connector "D". Check for continuity between ground and MAP sensor harness connector terminal No. 3 (Red/Green wire). (Scheme 6) If continuity exists, check for short in Red/Green wire between PCM 16-pin connector "D" and MAP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

Scheme 6

Scheme 6
Scheme 6

Except D16Y5 M/T

  1. Turn ignition on. Check MAP sensor using scan tool. If about 30 in. Hg is not indicated, go to next step. If about 30 in. Hg is indicated, problem is intermittent. Check for poor connections or loose wires at MAP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition off and disconnect MAP sensor 3-pin connector. Turn ignition on. Measure voltage between MAP sensor harness connector terminals No. 1 (Yellow/Red wire) and No. 2 (Green/White wire). (Scheme 6) If about 5.0 volts exists, go to next step. If about 5.0 volts does not exist, check for open in Yellow/Red wire between PCM 31-pin connector "C" terminal No. 19 and MAP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Check MAP sensor using scan tool. If about 0.6 in. Hg or less is indicated, go to next step. If about 0.6 in. Hg or less is not indicated, replace MAP sensor.
  4. Turn ignition off. Disconnect PCM 31-pin connector "C". see scheme 3 Check for continuity between ground and MAP sensor harness connector terminal No. 3 (Red/Green wire). (Scheme 6) If continuity exists, check for short in Red/Green wire between PCM 31-pin connector "C" and MAP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Turn ignition on. Using scan tool, check throttle position. If reading is about 10 percent (.49 volt) with throttle fully closed and 90 percent (4.5 volts) with throttle fully opened, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at TP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. If reading is not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor 3-pin connector. Turn ignition on. Measure voltage between TP sensor harness connector terminals No. 1 (Green/Black wire) and No. 3 (Yellow/Blue wire). (Scheme 6) If about 5.0 volts does not exist, go to next step. If about 5.0 volts exists, go to step 4.
  3. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 10 (Yellow/Blue wire) and No. 11 (Green/Black wire). see scheme 4 If about 5.0 volts exists, check for open in Yellow/Blue wire between PCM 16-pin connector "D" and TP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5.0 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  4. Turn ignition off. Measure resistance between TP sensor connector terminals No. 1 and 2 with throttle fully closed. (Scheme 6) If resistance is about 500-900 ohms, go to next step. If resistance is not as specified, replace throttle body (TP sensor cannot be serviced separately).
  5. Measure resistance between TP sensor terminals No. 2 and 3 with throttle fully closed. If resistance is about 3600-5400 ohms, go to next step. If resistance is not as specified, replace throttle body (TP sensor cannot be serviced separately).
  6. Reconnect TP sensor 3-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 1 (Red/Black wire) and No. 11 (Green/Black wire). see scheme 4 If voltage is about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. On D16Y5 engine with Continuously Variable Transmission (CVT), if voltage is not as specified, go to next step. On all other engines, if voltage is not as specified, check for short in Red/Black wire between PCM, TCM and TP sensor connector.
  7. On D16Y5 engine with CVT, turn ignition off. Disconnect Transmission Control Module (TCM) 22-pin connector. TCM is located below left side of instrument panel, behind left kick panel. Turn ignition on. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 1 (Red/Black wire) and No. 11 (Green/Black wire). see scheme 4 If voltage is about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open, replace TCM. If voltage is not as specified, check for short in Red/Black wire between PCM, TCM and TP sensor connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  1. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Turn ignition off. Turn ignition on. Using scan tool, check throttle position. If reading is about 10 percent (.49 volt) with throttle fully closed and 90 percent (4.5 volts) with throttle fully opened, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at TP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. If reading is not as specified, go to next step.
  2. Turn ignition off. Disconnect TP sensor 3-pin connector. Turn ignition on. Measure voltage between TP sensor harness connector terminals No. 1 (Green/Black wire) and No. 3 (Yellow/Blue wire). (Scheme 6) If about 5.0 volts does not exist, go to next step. If about 5.0 volts exists, go to step 4.
  3. Using backprobe set, measure voltage between PCM 31-pin connector "C" terminals No. 18 (Green/Black wire) and No. 28 (Yellow/Blue wire). see scheme 3 If about 5.0 volts exists, check for open in Yellow/Blue wire between PCM 31-pin connector "C" and TP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5.0 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  4. Turn ignition off. Measure resistance between TP sensor connector terminals No. 1 and 2 with throttle fully closed. (Scheme 6) If resistance is about 500-900 ohms, go to next step. If resistance is not as specified, replace throttle body (TP sensor cannot be serviced separately).
  5. Measure resistance between TP sensor connector terminals No. 2 and 3 with throttle fully closed. (Scheme 6) If resistance is about 4500 ohms, go to next step. If resistance is not as specified, replace throttle body (TP sensor cannot be serviced separately).
  6. Reconnect TP sensor 3-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 31-pin connector "C" terminals No. 18 (Green/Black wire) and No. 27 (Red/Black wire). see scheme 3 If voltage is about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If voltage is not about 0.5 volt with throttle fully closed and 4.5 volts with throttle fully open, check for short in Green/Black wire between PCM connector and TP sensor.
  1. Turn ignition on. Check TP sensor using scan tool. If reading is not about 10 percent (.49 volt) with throttle fully closed and 90 percent (4.5 volts) with throttle fully opened, go to next step. If reading is about 10 percent with throttle fully closed and 90 percent with throttle fully opened, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at TP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition off. Disconnect TP sensor 3-pin connector. Turn ignition on. Measure voltage between TP sensor harness connector terminals No. 1 (Green/Black wire) and No. 3 (Yellow/Blue wire). (Scheme 6) If about 5.0 volts does not exist, go to next step. If about 5.0 volts exists, replace throttle body (TP sensor is not serviced separately).
  3. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 10 (Yellow/Blue wire) and No. 11 (Green/Black wire) on all other models. see scheme 4 If about 5.0 volts exists, check for open in Green/Black wire between PCM and TP sensor connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5.0 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Turn ignition off. Turn ignition on. Check TP sensor using scan tool. If reading is not about 10 percent (.49 volt) with throttle fully closed and 90 percent (4.5 volts) with throttle fully opened, go to next step. If reading is about 10 percent with throttle fully closed and 90 percent with throttle fully opened, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at TP sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition off. Disconnect TP sensor 3-pin connector. Turn ignition on. Measure voltage between TP sensor harness connector terminals No. 1 (Green/Black wire) and No. 3 (Yellow/Blue wire). (Scheme 6) If about 5.0 volts does not exist, go to next step. If about 5.0 volts exists, replace throttle body (TP sensor is not serviced separately).
  3. Using backprobe set, measure voltage between PCM 31-pin connector "C" terminals No. 18 (Green/Black wire) and No. 28 (Yellow/Blue wire). see scheme 3 If about 5.0 volts exists, check for open in Green/Black wire between PCM connector and TP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5.0 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

Random Misfire Occurs During Low RPM & Low Engine Load

Check for

  1. EGR system malfunction on D16Y5 engine. See «DTC P0401»(ref-2658-S04157921532000041100000) , «DTC P1491»(ref-2658-S34757008012000041100000) and «DTC P1498»(ref-2658-S22327109222000041100000) testing.
  2. Correct fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.
  3. Crankshaft Position (CKP) sensor malfunction. See «DTC P0335 and DTC P0336»(ref-2658-S13919168822000041100000) testing.
  4. Valves incorrectly adjusted.

Random Misfire Occurs During Acceleration

Check for

  1. Worn or broken spark plug wires.
  2. Worn or damaged distributor ignition housing.
  3. Correct fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.
  4. Malfunctioning ignition control module. See IGNITION CONTROL MODULE under IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.

Random Misfire Occurs During High Engine RPM & Load, Or Under Other Random Conditions

Check for

  1. Correct fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.
  2. Worn or broken spark plug wires.
  3. Worn or damaged distributor ignition housing.
  4. Malfunctioning ignition control module. See IGNITION CONTROL MODULE under IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.
  5. Crankshaft Position (CKP) sensor malfunction. See «DTC P0335 and DTC P0336»(ref-2658-S13919168822000041100000) testing.
  6. Valves incorrectly adjusted.

No Problems Are Found

Check for

  1. Insufficient fuel pressure or inadequate fuel flow.
  2. Clogging, blocked or leaking fuel line.
  3. Clogged fuel filter.
  4. Stuck open fuel pressure regulator.
  5. EGR system malfunction (D16Y5 engine).
  6. Distributor malfunction.
  7. Open or short in ignition coil wire.
  8. Malfunctioning ignition control module. See IGNITION CONTROL MODULE under IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.
  9. Carbon deposits on valves.
  10. Low engine compression.
  11. Fuel octane level less than specification.
  12. VTEC system malfunction (B16A2, D16Y5 or D16Y8 engine).
  13. Heated Oxygen Sensor (HO2S) or HO2S circuit malfunction. Repair as necessary.
  1. Check Fuel Tank Pressure (FTP) sensor vacuum lines for incorrect routing, leaks, breaks and/or clogging. Repair or replace vacuum lines as necessary. If vacuum lines are okay, go to next step.
  2. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Remove fuel tank filler cap. Turn ignition on. Check FTP sensor voltage using an scan tool or using backprobe set, measure voltage between ground and PCM 16-pin connector "D" terminal No. 15 (Light Green wire). see scheme 4 If about 2.5 volts does not exist, go to next step. If about 2.5 volts exists, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at PCM and FTP sensor connectors. Check for poor connections or loose wires at Green 22-pin connector located below right side of dash, below ABS control unit. Check for poor connection or loose wires at Gray 14-pin (GX model) or 20-pin (except GX model) connector located in left kick panel, behind cruise control unit, above underdash fuse/relay box. Also check for poor connections or loose wires at fuel pump pigtail connector located under fuel pump access panel. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  3. Turn ignition off and reinstall fuel tank filler cap. Disconnect FTP sensor 3-pin connector. Turn ignition on. Measure voltage between FTP sensor harness connector terminals No. 1 (Yellow/Blue wire) and No. 2 (Green/Black wire). (Scheme 6) If about 5 volts exists, go to next step. If about 5 volts does not exist, check for open in Yellow/Blue wire between FTP sensor connector and PCM 16-pin connector "D" terminal No. 10. See appropriate wiring diagram in WIRING DIAGRAMS article.
  4. Measure voltage between FTP sensor 3-pin harness connector terminals No. 2 (Green/Black wire) and No. 3 (Light Green wire). (Scheme 6) If about 5 volts does not exist, go to next step. If about 5 volts exists, replace FTP sensor.
  5. Turn ignition off. Disconnect PCM 16-pin connector "D". Check for continuity between ground and FTP sensor harness connector terminal No. 3 (Light Green wire). If continuity exists, check for short in Light Green wire between PCM 16-pin connector "D" and FTP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Check Fuel Tank Pressure (FTP) sensor vacuum lines for incorrect routing, leaks, breaks and/or clogging. Repair or replace vacuum lines as necessary. If vacuum lines are okay, go to next step.
  2. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Remove fuel tank filler cap. Turn ignition on. Check FTP sensor voltage using an scan tool or using backprobe set, measure voltage between ground and PCM 32-pin connector "A" terminal No. 29 (Light Blue wire). see scheme 1 If about 2.5 volts does not exist, go to next step. If about 2.5 volts exists, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at PCM and FTP sensor connectors. Check for poor connections or loose wires at Green 22-pin connector located below right side of dash, below ABS control unit. Check for poor connection or loose wires at Gray 14-pin (GX model) or 20-pin (except GX model) connector located in left kick panel, behind cruise control unit, above underdash fuse/relay box. Also check for poor connections or loose wires at fuel pump pigtail connector located under fuel pump access panel. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  3. Turn ignition off and reinstall fuel tank filler cap. Disconnect FTP sensor 6-pin connector. Turn ignition on. Measure voltage between FTP sensor harness connector terminals No. 5 (Yellow/Blue wire) and No. 6 (Green/Black wire). (Scheme 6) If about 5 volts exists, go to next step. If about 5 volts does not exist, check for open in Yellow/Blue wire between FTP sensor connector and PCM 31-pin connector "C" terminal No. 28. see scheme 3 See appropriate wiring diagram in WIRING DIAGRAMS article.
  4. Measure voltage between FTP sensor 6-pin harness connector terminals No. 6 (Green/Black wire) and No. 2 (Light Green wire). (Scheme 6) If about 5 volts does not exist, go to next step. If about 5 volts exists, replace FTP sensor.
  5. Turn ignition off. Disconnect PCM 32-pin connector "A". Check for continuity between ground and FTP sensor harness connector terminal No. 2 (Light Green wire). If continuity exists, check for short in Light Green wire between PCM 32-pin connector "A" and FTP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Check Fuel Tank Pressure (FTP) sensor vacuum lines for incorrect routing, leaks, breaks and/or clogging. Repair or replace vacuum lines as necessary. If vacuum lines are okay, go to next step.
  2. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Remove fuel tank filler cap. Turn ignition on. Check FTP sensor voltage using an scan tool or using backprobe set, measure voltage between ground and PCM 16-pin connector "D" terminal No. 15 (Light Green wire). see scheme 4 If about 2.5 volts does not exist, go to next step. If about 2.5 volts exists, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at PCM and FTP sensor connectors. Check for poor connections or loose wires at Green 22-pin connector located below right side of dash, below ABS control unit. Check for poor connection or loose wires at Gray 14-pin (GX model) or 20-pin (except GX model) connector located in left kick panel, behind cruise control unit, above underdash fuse/relay box. Also check for poor connections or loose wires at fuel pump pigtail connector located under fuel pump access panel. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  3. Turn ignition off and reinstall fuel tank filler cap. Disconnect FTP sensor 3-pin connector. Turn ignition on. Measure voltage between FTP sensor harness connector terminals No. 1 (Yellow/Blue wire) and No. 2 (Green/Black wire). (Scheme 6) If about 5 volts exists, go to next step. If about 5 volts does not exist, check for open in Green/Black wire between FTP sensor connector and PCM 16-pin connector "D" terminal No. 11. See appropriate wiring diagram in WIRING DIAGRAMS article.
  4. Measure voltage between FTP sensor 3-pin harness connector terminals No. 2 (Green/Black wire) and No. 3 (Green/Red wire). (Scheme 6) If about 5 volts does not exist, go to next step. If about 5 volts exists, replace FTP sensor.
  5. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 11 (Green/Black wire) and No. 15 (Light Green wire). see scheme 4 See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5 volts exists, check for open in Light Green wire between PCM 16-pin connector "D" and FTP sensor. If about 5 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Check Fuel Tank Pressure (FTP) sensor vacuum lines for incorrect routing, leaks, breaks and/or clogging. Repair or replace vacuum lines as necessary. If vacuum lines are okay, go to next step.
  2. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Remove fuel tank filler cap. Turn ignition on. Check FTP sensor voltage using an scan tool or using backprobe set, measure voltage between ground and PCM 32-pin connector "A" terminal No. 29 (Light Green wire). see scheme 1 If about 2.5 volts does not exist, go to next step. If about 2.5 volts exists, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at PCM and FTP sensor connectors. Check for poor connections or loose wires at Green 22-pin connector located below right side of dash, below ABS control unit. Check for poor connection or loose wires at Gray 14-pin (GX model) or 20-pin (except GX model) connector located in left kick panel, behind cruise control unit, above underdash fuse/relay box. Also check for poor connections or loose wires at fuel pump pigtail connector located under fuel pump access panel. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  3. Turn ignition off and reinstall fuel tank filler cap. Disconnect FTP sensor 6-pin connector. Turn ignition on. Measure voltage between FTP sensor harness connector terminals No. 5 (Yellow/Blue wire) and No. 6 (Green/Black wire). (Scheme 6) If about 5 volts exists, go to next step. If about 5 volts does not exist, check for open in Green/Black wire between FTP sensor connector and PCM 31-pin connector "C" terminal No. 18. see scheme 3 See appropriate wiring diagram in WIRING DIAGRAMS article.
  4. Measure voltage between FTP sensor 6-pin harness connector terminals No. 6 (Green/Black wire) and No. 2 (Light Green wire). (Scheme 6) If about 5 volts does not exist, go to next step. If about 5 volts exists, replace FTP sensor.
  5. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 29 (Light Green wire) and PCM 31-pin connector "C" terminal No. 18 (Green/Black wire). See appropriate wiring diagram in WIRING DIAGRAMS article. If about 5 volts exists, check for open in Light Green wire between PCM 32-pin connector "A" and FTP sensor. If about 5 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  1. Test drive vehicle. Using scan tool, check vehicle speed. If correct speed is not indicated, go to next step. If correct speed is indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at VSS and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  2. Turn ignition off. Block rear wheels and set parking brake. Raise and support front of vehicle. Turn ignition on. Block right front wheel and slowly rotate left front wheel by hand. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 9 (Brown/Black wire) and PCM 31-pin connector "C" terminal No. 18 (Blue/White wire). see scheme 1and see scheme 3. If voltage does not pulse between zero and 5 volts, go to next step. If voltage pulses between zero and 5 volts, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  3. Turn ignition off. Disconnect PCM 31-pin connector "C". Turn ignition on. Block right front wheel and slowly rotate left front wheel by hand. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 9 (Brown/Black wire) and PCM 31-pin harness connector "C" terminal No. 18 (Blue/White wire). If voltage pulses between zero and 5 volts, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If voltage does not pulse between zero and 5 volts, check for short in Blue/White wire between PCM, TCM and VSS. Also check for open in Blue/White wire between PCM and VSS. See appropriate wiring diagram in WIRING DIAGRAMS article. If wire is okay, check VSS. See VEHICLE SPEED SENSOR (VSS) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article.
  1. Test drive vehicle. Using scan tool, check vehicle speed. If correct speed is not indicated, go to next step. If correct speed is indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at VSS and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.
  2. Turn ignition off. Block rear wheels and set parking brake. Raise and support front of vehicle. Turn ignition on. Block right front wheel and slowly rotate left front wheel by hand. Using backprobe set, measure voltage between PCM 25-pin connector "B" terminal No. 20 (Brown/Black wire) and PCM 31-pin connector "C" terminal No. 23 (Blue/White wire). see scheme 2and see scheme 3. If voltage does not pulse between zero and 5 volts or battery voltage, go to next step. If voltage pulses between zero and 5 volts or battery voltage, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  3. Turn ignition off. Disconnect PCM 31-pin connector "C". Turn ignition on. Block right front wheel and slowly rotate left front wheel by hand. Using backprobe set, measure voltage between PCM 25-pin connector "B" terminal No. 20 (Brown/Black wire) and PCM 31-pin connector "C" terminal No. 23 (Blue/White wire). see scheme 2and see scheme 3. If voltage pulses between zero and 5 volts or battery voltage, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM. If voltage does not pulse between zero and 5 volts or battery voltage, check for short in Blue/White wire between PCM, TCM and VSS. Also check for open in Blue/White wire between PCM and VSS. See appropriate wiring diagram in WIRING DIAGRAMS article. If wire is okay, check VSS. See VEHICLE SPEED SENSOR (VSS) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article.
  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Start engine and turn headlights on. If DTC P1298 is indicated, go to next step. If DTC P1298 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at ELD and PCM connectors. Also check for poor connections or loose wires at Green 22-pin connector located below right side of dash, behind kick panel, below ABS control unit. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition and headlights off. Disconnect ELD 3-pin connector. Turn ignition on. Measure voltage between ground and ELD harness connector terminal No. 1 (Black/White wire). see scheme 10 If continuity exists, go to next step. If continuity does not exist, check for open in Black/White wire between ELD and No. 15 ALTERNATOR SP SENSOR (7.5-amp) fuse.
  3. Turn ignition off. Check for continuity between ground and ELD harness connector terminal No. 2 (Black wire). see scheme 10 If continuity exists, go to next step. If continuity does not exist, check for open in Black wire between ELD and ground connector G402. Ground connector G402 is located behind right side of dash panel, right of blower fan.
  4. Using backprobe set, check for continuity between ELD harness connector terminal No. 3 (Green/Red wire) and PCM 16-pin connector "D" terminal No. 16. see scheme 4and see scheme 10. If continuity exists, go to next step. If continuity does not exist, check for open in Green/Red wire between PCM 16-pin connector "D" and ELD. See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Reconnect ELD 3-pin connector. Start engine and allow it to idle. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 9 (Brown/Black wire) and PCM 16-pin connector "D" terminal No. 16 (Green/Red wire). see scheme 1and see scheme 4. While measuring voltage, turn headlights on low. If voltage does not decrease, replace ELD. If voltage decreases, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Start engine and turn headlights on. If DTC P1298 is indicated, go to next step. If DTC P1298 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at ELD and PCM connectors. Also check for poor connections or loose wires at Green 22-pin connector located below right side of dash, behind kick panel, below ABS control unit. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition and headlights off. Disconnect ELD 3-pin connector. Turn ignition on. Measure voltage between ground and ELD harness connector terminal No. 1 (Black/White wire). see scheme 10 If continuity exists, go to next step. If continuity does not exist, check for open in Black/White wire between ELD and No. 15 ALTERNATOR SP SENSOR (7.5-amp) fuse.
  3. Turn ignition off. Check for continuity between ground and ELD harness connector terminal No. 2 (Black wire). see scheme 10 If continuity exists, go to next step. If continuity does not exist, check for open in Black wire between ELD and ground connector G402. Ground connector G402 is located behind right side of dash panel, right of blower fan.
  4. Disconnect PCM 32-pin connector "A". Check for continuity in Green/Red wire between ELD harness connector terminal No. 3 and PCM 32-pin harness connector "A" terminal No. 30. see scheme 1and see scheme 10. If continuity exists, go to next step. If continuity does not exist, check for open in Green/Red wire between PCM 16-pin connector "D" and ELD. see scheme 4 See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Reconnect ELD 3-pin connector and PCM 32-pin connector "A". Start engine and allow it to idle. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 30 (Green/Red wire) and PCM 25-pin connector "B" terminal No. 20 (Brown/Black wire). see scheme 1and see scheme 2. While measuring voltage, turn headlights on low. If voltage does not decrease, replace ELD. If voltage decreases, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Start engine. If DTC P1336 and/or P1337 is indicated, go to next step. If DTC P1336 and P1337 are not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at CKF sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. Also check for loose CKF sensor mounting bolt. Repair as necessary.
  2. Turn ignition off. Disconnect CKF sensor Gray connector. On B16A2, CKF sensor Gray connector is located below of vehicle, left rear of engine, above inner constant velocity joint. On all models except B16A2, CKF sensor Gray connector is located at left side of engine, below left intake manifold runner. Measure resistance between CKF sensor Gray connector terminals No. 1 (White wire) and No. 3 (Blue wire). If resistance is 1600-3200 ohms, go to next step. If resistance is not 1600-3200 ohms, replace CKF sensor.
  3. Check for continuity between ground and CKF sensor Gray connector terminal No. 1 (White wire) and terminal No. 3 (Blue wire), individually. If continuity does not exist, go to next step. If continuity exists, replace CKF sensor.
  4. Turn ignition off. Reconnect CKF sensor Gray connector. Disconnect PCM 31-pin connector "C". see scheme 3 Measure resistance between PCM 31-pin harness connector "C" terminals No. 1 (Blue/Red wire) and No. 11 (White/Red wire). If resistance is 1600-3200 ohms, go to next step. If resistance is not 1600-3200 ohms, check for open in suspect wire between CKF sensor and PCM 31-pin connector "C". See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Check for continuity between ground and PCM 31-pin harness connector "C" terminal No. 1 (Blue/Red wire). If continuity exists, check for short in Blue/Red wire between PCM 31-pin connector "C" and CKF sensor. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Start engine. If DTC P1336 and/or P1337 is indicated, go to next step. If DTC P1336 and P1337 are not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at CKF sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. Also check for loose CKF sensor mounting bolt. Repair as necessary.
  2. Turn ignition off. Disconnect CKF sensor Gray connector. Measure resistance between CKF sensor Gray connector terminals No. 1 (White wire) and No. 3 (Blue wire). If resistance is 1600-3200 ohms, go to next step. If resistance is not 1600-3200 ohms, replace CKF sensor.
  3. Check for continuity between ground and CKF sensor Gray connector terminal No. 1 (White wire) and terminal No. 3 (Blue wire), individually. If continuity does not exist, go to next step. If continuity exists, replace CKF sensor.
  4. Turn ignition off. Reconnect CKF sensor Gray connector. Disconnect PCM 31-pin connector "C". see scheme 3 Measure resistance between PCM 31-pin harness connector "C" terminals No. 22 (Blue/Red wire) and No. 31 (White/Red wire). If resistance is 1600-3200 ohms, go to next step. If resistance is not 1600-3200 ohms, check for open in suspect wire between CKF sensor and PCM 31-pin connector "C". See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Check for continuity between ground and PCM 31-pin harness connector "C" terminal No. 22 (Blue/Red wire). If continuity exists, check for short in Blue/Red wire between PCM 31-pin connector "C" and CKF sensor. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  1. If either DTC P1456 or DTC P1457 sets, check for: Faulty fuel filler cap. Proper vacuum hose connections. Fuel tank leak. EVAP control canister Vent Shut Valve (VSV) malfunction. EVAP control canister VSV circuit malfunction. EVAP purge control solenoid valve malfunction. EVAP purge control solenoid valve circuit malfunction. EVAP by-pass solenoid valve malfunction. EVAP by-pass solenoid valve circuit malfunction. Fuel tank pressure sensor malfunction. Fuel tank pressure sensor circuit malfunction. EVAP control canister malfunction. Faulty throttle body. Repair as necessary. If no problems are found, go to next step.
  2. Disconnect EVAP control canister Vent Shut Valve (VSV) vacuum hose from EVAP 3-way valve and connect vacuum pump to hose. (Scheme 7) See VACUUM DIAGRAMS article. Remove EVAP control canister VSV from top of canister. Ensure EVAP control canister VSV 2-pin connector is connected. Turn ignition on and apply vacuum to hose. If EVAP control canister VSV does not hold a vacuum, go to next step. If EVAP control canister VSV holds a vacuum, disconnect EVAP control canister VSV 2-pin connector. Apply vacuum to EVAP control canister VSV vacuum hose. If EVAP control canister VSV holds a vacuum, replace EVAP control canister VSV. If EVAP control canister VSV does not hold a vacuum, check for short in Light Green/White wire between EVAP control canister VSV and PCM 32-pin connector "A" terminal No. 29. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Turn ignition off. Using backprobe set, connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 29 (Light Green/White wire). see scheme 1 Turn ignition on and apply vacuum to EVAP control canister VSV vacuum hose. If EVAP control canister VSV holds a vacuum, go to step 6). If EVAP control canister VSV does not hold a vacuum, go to next step.
  4. Turn ignition off. Disconnect EVAP control canister VSV 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP control canister VSV 2-pin harness connector terminal No. 2 (Black/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in wire between EVAP control canister VSV and No. 15 ALTERNATOR SP SENSOR (7.5-amp) fuse located in underdash fuse/relay box. See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Turn ignition off. Reconnect EVAP control canister VSV 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 10 (Black wire) and No. 29 (Light Green/White wire). see scheme 1 If battery voltage does not exist, check for open in Light Green/White wire between EVAP control canister VSV and PCM 32-pin connector "A". See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, replace EVAP control canister VSV.
  6. Reconnect EVAP control canister VSV vacuum hose to EVAP 3-way valve. Disconnect EVAP purge control solenoid valve vacuum hose from EVAP canister (upper left hose). (Scheme 7) See VACUUM DIAGRAMS article. Attach vacuum gauge to disconnected hose. Start engine and allow it to idle. Ensure engine coolant temperature is less than 154°F (68°C) and A/C off. Quickly increase engine speed to 3000 RPM and check for vacuum. If vacuum exists, go to next step. If vacuum does not exist, go to step 9.
  7. Disconnect EVAP purge control solenoid valve 2-pin connector. On D16Y7 engine, EVAP purge control solenoid valve is located at right side of engine, below air cleaner-to-air tube connection. On B16A2, D16Y5 and D16Y8, EVAP purge control solenoid valve is located below fuel injector rail cover. Quickly increase engine speed to 3000 RPM and check for vacuum. If vacuum does not exist, go to next step. If vacuum exists, inspect vacuum hose routing. See VACUUM DIAGRAMS article. If vacuum hose routing is okay, replace EVAP purge control solenoid valve.
  8. Turn ignition off. Disconnect PCM 32-pin connector "A". see scheme 1 Check for continuity between ground and EVAP purge control solenoid valve 2-pin harness connector terminal No. 2 (Red/Yellow wire). If continuity exists, check for short in Red/Yellow wire between EVAP purge control solenoid valve and PCM 32-pin connector "A" terminal No. 15. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  9. Turn ignition off. Set parking brake and block rear wheels. Raise and support front suspension with wheels off ground. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Check for vacuum at EVAP purge control solenoid valve vacuum hose with A/T in "2" position or M/T in 1st gear. Carefully increase engine speed quickly to 3000 RPM and check for vacuum. If vacuum does not exist, go to next step. If vacuum exists, Go to step 13.
  10. Turn ignition off. Disconnect EVAP purge control solenoid valve 2-pin connector. Start engine and allow it to idle at normal operating temperature. Measure voltage between EVAP purge control solenoid valve 2-pin harness connector terminals with A/T in "2" position or M/T in 1st gear. If battery voltage does not exist, go to next step. If battery voltage exists, check vacuum hose routing. If vacuum hose routing is okay, replace EVAP purge control solenoid valve.
  11. Measure voltage between ground and EVAP purge control solenoid valve 2-pin harness connector terminal No. 1 (Black/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in wire between EVAP purge control solenoid valve and No. 15 ALTERNATOR SP SENSOR (7.5 amp) fuse. See appropriate wiring diagram in WIRING DIAGRAMS article.
  12. Turn ignition off. Reconnect EVAP purge control solenoid valve 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal A10 (Black wire) and terminal A15 (Red/Yellow wire). see scheme 1 If battery voltage does not exist, check for open in Red/Yellow between EVAP purge control solenoid valve and PCM 32-pin connector "A". See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  13. Check EVAP 2-way valve. See EMISSION SYSTEMS & SUB SYSTEMS in SYSTEM & COMPONENT TESTING article. Replace EVAP 2-way valve if faulty. If EVAP 2-way valve is okay, disconnect vacuum hoses from EVAP 2-way valve. Connect vacuum pump to EVAP 2-way valve (port to EVAP canister) and apply vacuum. (Scheme 8) Turn ignition on. If 2-way valve holds a vacuum, go to step 15. If 2-way valve does not hold a vacuum, go to next step.
  14. Disconnect EVAP by-pass solenoid valve 2-pin connector. Apply vacuum to EVAP 2-way valve hose. If 2-way valve holds a vacuum, check for short in Blue wire between EVAP by-pass solenoid valve and PCM 32-pin connector "A" terminal No. 28. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article. If 2-way valve does not hold a vacuum, replace EVAP by-pass solenoid valve.
  15. Turn ignition off. Using backprobe set, connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 28 (Blue wire). see scheme 1 Turn ignition on and apply vacuum to 2-way valve. If 2-way valve holds a vacuum, go to next step. If 2-way valve does not hold a vacuum, check following components for leakage to atmosphere, and repair or replace as necessary: fuel filler cap, fuel tank, fuel vapor pipe, EVAP 2-way valve, EVAP by-pass solenoid valve, fuel tank pressure sensor, EVAP control canister, EVAP control canister VSV, EVAP purge control solenoid valve, and vacuum hoses and connections. See VACUUM DIAGRAMS article.
  16. Turn ignition off. Disconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP by-pass solenoid valve 2-pin harness connector terminal No. 1 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Black/White wire between EVAP by-pass solenoid valve connector and No. 15 ALTERNATOR SP SENSOR (7.5 amp) fuse. See appropriate wiring diagram in WIRING DIAGRAMS article.
  17. Turn ignition off. Reconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminals No. 10 (Black wire) and No. 28 (Blue wire). see scheme 1 If battery voltage exists, replace EVAP by-pass solenoid valve. If battery voltage does not exist, check for open in Blue wire between EVAP solenoid valve and PCM 32-pin connector "A" No. 28. See appropriate wiring diagram in WIRING DIAGRAMS article.

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8
Scheme 8
  1. If either DTC P1456 or DTC P1457 sets, check for: Faulty fuel filler cap. Proper vacuum hose connections. Fuel tank leak. EVAP control canister Vent Shut Valve (VSV) malfunction. EVAP control canister VSV circuit malfunction. EVAP purge control solenoid valve malfunction. EVAP purge control solenoid valve circuit malfunction. EVAP by-pass solenoid valve malfunction. EVAP by-pass solenoid valve circuit malfunction. Fuel tank pressure sensor malfunction. Fuel tank pressure sensor circuit malfunction. EVAP control canister malfunction. On-Board Refueling Vapor Recovery (ORVR) Vent Shut Valve (VSV) malfunction. ORVR vapor recirculation valve malfunction. Faulty throttle body. Repair as necessary. If no problems are found, go to next step.
  2. Disconnect EVAP control canister Vent Shut Valve (VSV) vacuum hose from EVAP 3-way valve and connect vacuum pump to hose. (Scheme 7) See VACUUM DIAGRAMS article. Remove EVAP control canister VSV from top of canister. Ensure EVAP control canister VSV 2-pin connector is connected. Turn ignition on and apply vacuum to hose. If EVAP control canister VSV does not hold a vacuum, go to next step. If EVAP control canister VSV holds a vacuum, disconnect EVAP control canister VSV 2-pin connector. Apply vacuum to EVAP control canister VSV vacuum hose. If EVAP control canister VSV holds a vacuum, replace EVAP control canister VSV. If EVAP control canister VSV does not hold a vacuum, check for short in Light Green/White wire between EVAP control canister VSV and PCM 32-pin connector "A" terminal No. 4. see scheme 1 See appropriate wiring diagram in WIRING DIAGRAMS article.
  3. Turn ignition off. Using backprobe set, connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 4 (Light Green/White wire). see scheme 1 Turn ignition on and apply vacuum to EVAP control canister VSV vacuum hose. If EVAP control canister VSV holds a vacuum, go to step 6. If EVAP control canister VSV does not hold a vacuum, go to next step.
  4. Turn ignition off. Disconnect EVAP control canister VSV 2-pin connector. EVAP control canister VSV 2-pin connector is located at right rear side of engine compartment, between battery and air intake tube. Turn ignition on. Measure voltage between ground and EVAP control canister VSV 2-pin connector terminal No. 2 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in wire between EVAP control canister VSV and No. 15 ALTERNATOR SP SENSOR (7.5-amp) fuse located in underdash fuse/relay box. See appropriate wiring diagram in WIRING DIAGRAMS article.
  5. Turn ignition off. Reconnect EVAP control canister VSV 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 4 (Light Green/White wire) and PCM 25-pin connector "B" terminal No. 2 (Black wire). see scheme 2 If battery voltage does not exist, check for open in Light Green/White wire between EVAP control canister VSV and PCM 32-pin connector "A". See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, replace EVAP control canister VSV.
  6. Reconnect vacuum hose to EVAP 3-way valve. Disconnect EVAP purge control solenoid valve vacuum hose from EVAP canister (upper left hose). (Scheme 7) See VACUUM DIAGRAMS article. Attach vacuum gauge to disconnected hose. Start engine and allow it to idle. Ensure engine coolant temperature is less than 154°F (68°C) and A/C is off. Quickly increase engine speed to 3000 RPM and check for vacuum. If vacuum exists, go to next step. If vacuum does not exist, go to step 9.
  7. Disconnect EVAP purge control solenoid valve 2-pin connector. On D16Y7 engine, EVAP purge control solenoid valve is located at right side of engine, below air cleaner-to-air tube connection. On B16A2, D16Y5 or D16Y8, EVAP purge control solenoid valve is located below fuel injector rail cover. Quickly increase engine speed to 3000 RPM and check for vacuum. If vacuum does not exist, go to next step. If vacuum exists, inspect vacuum hose routing. See VACUUM DIAGRAMS article. If vacuum hose routing is okay, replace EVAP purge control solenoid valve.
  8. Turn ignition off. Disconnect PCM 32-pin connector "A". see scheme 1 Check for continuity between ground and EVAP purge control solenoid valve harness connector terminal No. 2 (Red/Yellow wire). If continuity exists, check for short in Red/Yellow wire between EVAP purge control solenoid valve and PCM 32-pin connector "A" terminal No. 6. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  9. Turn ignition off. Set parking brake and block rear wheels. Raise and support front suspension with wheels off ground. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Check for vacuum at EVAP purge control solenoid valve vacuum hose with A/T in "2" position or M/T in 1st gear. Carefully increase engine speed quickly to 3000 RPM and check for vacuum. If vacuum does not exist, go to next step. If vacuum exists, Go to step 13.
  10. Turn ignition off. Disconnect EVAP purge control solenoid valve 2-pin connector. Start engine and allow it to idle at normal operating temperature. Measure voltage between EVAP purge control solenoid valve harness connector terminals. If battery voltage does not exist, go to next step. If battery voltage exists, check vacuum hose routing. If vacuum hose routing is okay, replace EVAP purge control solenoid valve.
  11. Measure voltage between ground and EVAP purge control solenoid valve 2-pin harness connector terminal No. 1 (Black/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in wire between EVAP purge control solenoid valve and No. 15 ALTERNATOR SP SENSOR (7.5 amp) fuse. See appropriate wiring diagram in WIRING DIAGRAMS article.
  12. Turn ignition off. Reconnect EVAP purge control solenoid valve 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 6 (Red/Yellow wire) and PCM 25-pin connector "B" terminal No. 2 (Black wire). see scheme 1and see scheme 2. If battery voltage does not exist, check for open in Red/Yellow between EVAP purge control solenoid valve and PCM 32-pin connector "A". See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  13. Check EVAP 2-way valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. Replace EVAP 2-way valve if faulty. If EVAP 2-way valve is okay, using transmission jack lift up on fuel tank. Disconnect vacuum hoses from EVAP 2-way valve. Connect vacuum pump to EVAP 2-way valve (port to EVAP canister) and apply vacuum. (Scheme 9) Turn ignition on. If 2-way valve holds a vacuum, go to step 15. If 2-way valve does not hold a vacuum, go to next step.
  14. Disconnect EVAP by-pass solenoid valve 2-pin connector. Apply vacuum to hose. If 2-way valve holds a vacuum, check for short in Blue wire between EVAP by-pass solenoid valve connector and PCM 32-pin connector "A" terminal No. 28. See appropriate wiring diagram in WIRING DIAGRAMS article. If 2-way valve does not hold a vacuum, replace EVAP by-pass solenoid valve.
  15. Turn ignition off. Connect a fused jumper wire between ground and PCM 32-pin connector "A" terminal No. 3 (Blue wire). see scheme 1 Turn ignition on and apply vacuum to 2-way valve. If 2-way valve holds a vacuum, go to next step. If 2-way valve does not hold a vacuum, check following components for leakage to atmosphere, and repair or replace as necessary: fuel filler cap, fuel tank, fuel vapor pipe, EVAP 2-way valve, EVAP by-pass solenoid valve, fuel tank pressure sensor, EVAP control canister, EVAP control canister VSV, EVAP purge control solenoid valve, On-Board Refueling Vapor Recovery (ORVR) Vent Shut Valve (VSV), ORVR vapor recirculation valve and vacuum hoses and connections. See VACUUM DIAGRAMS article.
  16. Turn ignition off. Disconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP by-pass solenoid valve 2-pin connector terminal No. 1 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Black/White wire between EVAP by-pass solenoid valve and No. 15 ALTERNATOR SP SENSOR (7.5-amp) fuse. See appropriate wiring diagram in WIRING DIAGRAMS article.
  17. Turn ignition off. Reconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Using backprobe set, measure voltage between PCM 32-pin connector "A" terminal No. 3 (Blue wire) and 25-pin connector "B" terminal No. 2 (Black wire). If battery voltage exists, replace EVAP by-pass solenoid valve. If battery voltage does not exist, check for open in Blue wire between EVAP solenoid valve and PCM 32-pin connector "A". See appropriate wiring diagram in WIRING DIAGRAMS article.

Scheme 9

Scheme 9
Scheme 9

Continuously Variable Transmission (CVT)

  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Connect SCS service connector. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Drive vehicle for about 10 minutes. Maintain engine speed at 1700-2500 RPM. If DTC P1491 is indicated, go to next step. If DTC P1491 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at EGR valve and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition off. Disconnect vacuum hose from top of EGR valve. See VACUUM DIAGRAMS article. Connect vacuum pump/gauge to hose. Start engine and allow it to idle. If vacuum does not exist, go to next step. If vacuum exists, disconnect EGR solenoid valve 2-pin connector. Recheck EGR vacuum hose for vacuum. If vacuum exists, check EGR system hose routing. If hose routing is okay, replace EGR control solenoid valve. If vacuum does not exist, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM.
  3. Connect vacuum pump/gauge to EGR valve. With engine at idle, apply 8 in. Hg vacuum to EGR valve. If engine stalls or runs rough, and EGR valve holds vacuum, go to next step. If engine does not stall or run rough, or EGR valve does not hold vacuum, replace EGR valve.
  4. Turn ignition off. Disconnect EGR valve lift sensor 3-pin connector. EGR valve lift sensor 3-pin connector is located at top of EGR, on right side of engine. Turn ignition on. Measure voltage between EGR valve lift sensor harness connector terminals No. 2 and No. 3. If 5 volts exist, go to step 6. If 5 volts does not exist, go to next step.
  5. Using backprobe set, measure voltage between PCM 31-pin connector "C" terminals No. 18 (Green/Black wire) and No. 28 (Yellow/Blue wire). see scheme 3 If 5 volts exist, check for open in Yellow/Blue wire between PCM 31-pin connector "C" and EGR valve. If 5 volts does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  6. Turn ignition off. Measure resistance between EGR valve lift sensor terminals No. 1 and No. 2. (Scheme 6) If resistance is 100,000 ohms or higher, replace EGR valve. If resistance is not 100,000 or higher, go to next step.
  7. Measure resistance between EGR valve lift sensor terminals No. 1 and No. 3. (Scheme 6) If resistance is 100,000 ohms or higher, go to next step. If resistance is not 100,000 or higher, replace EGR valve.
  8. Reconnect EGR valve lift sensor connector. Turn ignition on. Using backprobe set, measure voltage between PCM 31-pin connector "C" terminals No. 6 (White/Black wire) and No. 18 (Green/Black wire). If 1.2 volts exists, go to step 10. If 1.2 volts does not exist, go to next step.
  9. Using backprobe set, check for continuity between ground and PCM 31-pin connector "C" terminal No. 6 (White/Black wire). If continuity does not exist, check for open in White/Black wire between EGR valve and PCM 31-pin connector "C". If continuity exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  10. Ensure vacuum pump/gauge is connected to vacuum hose from top of EGR valve. Disconnect EGR valve lift connector. Start engine and allow it to idle. Using fused jumper wire, connect battery voltage to EGR control solenoid valve terminal No. 1 (Black/Yellow wire). See appropriate wiring diagram in WIRING DIAGRAMS article. Using a second fused jumper wire, ground EGR control solenoid valve terminal No. 2 (Red wire). Observe vacuum gauge. If there is about 8.0 in. Hg vacuum within one second, go to step 12. If there is not about 8.0 in. Hg vacuum within one second, go to next step.
  11. Turn ignition off. Check vacuum hoses between EGR control solenoid valve, EGR valve and intake manifold for leaks, restrictions or misrouting. See VACUUM DIAGRAMS article. Repair or replace hoses as necessary. If hoses are okay, replace EGR control solenoid valve.
  12. Turn ignition off. Disconnect PCM 25-pin connector "B". see scheme 2 Check for continuity in Red wire between PCM 25-pin connector "B" terminal No. 6 and EGR control solenoid valve harness connector terminal No. 2. If continuity exists, go to next step. If continuity does not exist, check for open in Red wire between PCM 25-pin connector "B" and EGR valve connector. See appropriate wiring diagram in WIRING DIAGRAMS article.
  13. Turn ignition off and remove jumper wires. Disconnect EGR solenoid valve 2-pin connector. Disconnect PCM 32-pin connector "A". Check for continuity in Red wire between PCM 32-pin connector terminal No. 7 and EGR solenoid valve harness connector terminal No. 2. If continuity exists, go to next step. If continuity does not exist, check for open in Red wire between PCM 32-pin connector "A" and EGR valve connector. See appropriate wiring diagram in WIRING DIAGRAMS article.
  14. Check for continuity between ground and EGR valve harness connector terminal No. 2 (Red wire). See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, go to next step. If continuity exists, check for short in Red wire between PCM 25-pin connector "B" and EGR valve connector. See appropriate wiring diagram in WIRING DIAGRAMS article.
  15. Check for continuity between ground and EGR control solenoid valve harness connector terminal No. 1 (Black wire). If continuity does not exist, check for open in Black wire between EGR control solenoid valve and ground connection located at right front of engine, below air cleaner box. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity exists, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

M/T

  1. Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Connect SCS Service Connector (07PAZ-0010100). Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Drive vehicle for about 10 minutes. Maintain engine speed at 1700-2500 RPM. If DTC P1491 is indicated, go to next step. If DTC P1491 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at EGR valve lift sensor and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article.
  2. Turn ignition off. Disconnect EGR valve lift sensor connector. Start engine and allow it to idle. Measure voltage between EGR valve lift sensor harness connector terminals No. 4 (Black wire) and No. 6 (Pink wire). (Scheme 10) If battery voltage does not exist, go to next step. If battery voltage exists, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.
  3. Turn ignition off. Turn ignition on. Measure voltage between EGR valve lift sensor harness connector terminals No. 2 (Green/Black wire) and No. 3 (Yellow/Blue wire). If 5 volts exists, go to next step. If 5 volts does not exist, replace EGR valve.
  4. Using backprobe set, measure voltage between ECM 16-pin connector "D" terminals No. 10 (Yellow/Blue wire) and No. 11 (Green/Black wire). If 5 volts does not exist, go to next step. If 5 volts exists, check for open in Green/Black wire between EGR valve lift sensor connector and ECM 16-pin connector "D".
  5. Turn ignition off. Measure resistance between EGR valve lift sensor terminals No. 1 and No. 2. See. (Scheme 10). If resistance is 100,000 ohms or higher, replace EGR valve. If resistance is not 100,000 or higher, go to next step.
  6. Measure resistance between EGR valve lift sensor terminals No. 1 and No. 3. (Scheme 10) If resistance is 100,000 ohms or higher, go to next step. If resistance is not 100,000 or higher, replace EGR valve.
  7. Reconnect EGR valve lift sensor connector. Turn ignition on. Using backprobe set, measure voltage between PCM 16-pin connector "D" terminals No. 9 (White/Black wire) and No. 11 (Green/Black wire). If 1.2 volts exists, go to step 9. If 1.2 volts does not exist, go to next step.
  8. Using backprobe set, check for continuity between ground and PCM 16-pin connector "D" terminal No. 9 (White/Black wire). If continuity does not exist, check for open in White/Black wire between EGR valve and PCM 16-pin connector "D". If continuity exists, check for short in White/Black wire between EGR valve and PCM 16-pin connector "D".
  9. Turn ignition off. Disconnect EGR valve lift sensor connector. Using a fused jumper wire, connect battery voltage to EGR valve lift sensor terminal No. 6 (Pink wire). (Scheme 10) Start engine and allow it to idle. Using a second fused jumper wire, ground EGR valve lift sensor terminal No. 4 (Black wire). If engine stalls or runs rough, go to next step. If engine does not stall or run rough, replace EGR valve.
  10. Turn ignition off and disconnect jumper wires from EGR valve lift sensor connector. Disconnect PCM 32-pin connector "A". Check for continuity in Pink wire between PCM 32-pin connector "A" harness connector terminal No. 7 and EGR valve lift sensor harness connector terminal No. 6. see scheme 1and (Scheme 10). If continuity exists, go to next step. If continuity does not exist, check for open in Pink wire between PCM 32-pin connector "A" and EGR valve. See appropriate wiring diagram in WIRING DIAGRAMS article.
  11. Check for continuity between ground and PCM 32-pin connector "A" harness connector terminal No. 7 (Pink wire). If continuity does not exist, go to next step. If continuity exists, check for short in Pink wire between PCM 32-pin connector "A" and EGR valve. See appropriate wiring diagram in WIRING DIAGRAMS article.
  12. Check for continuity between ground and EGR valve lift sensor harness connector terminal No. 4 (Black wire). (Scheme 10) If continuity does not exist, check for open in Black wire between EGR valve harness connector and ground connection located at thermostat housing. See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity exists, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.

Scheme 10

Scheme 10
Scheme 10

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