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Engine Controls - Self-Diagnostics - 2.2L: Other Isuzu Rodeo II

Testing & Diagnostics 1 illustration ~2741 words

TRIP DETECTION LOGIC

OBD-II data streams are prioritized. When 2 messages attempt to establish communications on a data line at the same time, only the message with higher priority will continue. A new segment of software called the Diagnostic Executive coordinates the protocol for recording and displaying diagnostic procedures.

Trip is a single key-on-run-key-off cycle which satisfies the enable criteria for a specific diagnostic function. Criteria may vary slightly to satisfy differing diagnostic functions. For this reason, the definition of trip may vary with the specific application. The Diagnostic Executive uses trip information in setting and erasing DTCs.

After engine has reached normal operating temperature, Diagnostic Executive checks if on-board diagnostic tests have been completed since last ignition cycle. Executive checks if tests have passed during current ignition cycle, and if fault(s) identified by diagnostic tests is currently active. Executive also checks if fault identified has been active during current ignition cycle and what operating conditions were present at the time of failure.

A malfunction will set one of 4 types of DTC

  1. Type A Turns the MIL on the first time an emission related failure occurs. The MIL may flash at a rate of once per second to alert the operator of potentially damaging levels of misfire, which could possibly destroy the catalytic converter. History DTC, Freeze Frame and Fail Record are stored, and Fail Records are updated each time current diagnostic test fails.
  2. Type B Will only turn MIL on if an emission related condition occurs during 2 consecutive driving cycles. Conditions such as incorrect fuel trim will be stored in the freeze-frame data until the fault is detected a second time.
  3. Type C This is a non-emission related type DTC and will not activate the MIL. It will turn on a CHECK TRANSMISSION service light, or other non-MIL service reminder light.
  4. Type D Is non-emission related, and will not turn on service light, but will store DTCs for present faults.

PRELIMINARY CHECK

Perform OBD-II system check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK . When it is established that OBD-II system is functioning properly, retrieve DTCs. See RETRIEVING CODES .

Hard Failures

Hard failures cause Malfunction Indicator Light (MIL) to glow and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic tests. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If a sensor fails, Powertrain Control Module (PCM) will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, vehicle runs but driveability will not be optimum.

Intermittent Failures

Intermittent failures may cause MIL to flicker or glow and go out after intermittent fault goes away. However, corresponding DTC will be retained in PCM memory. If related fault does not reoccur within a certain time frame, related DTC will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

FREEZE-FRAME DATA

Engine operating conditions that cause MIL to illuminate are recorded in PCM memory. This record, called freeze frame data, is a snap shot of driving conditions that are recorded on PCM freeze frame buffer, and is constantly updated with the most current information.

Freeze frame data can only be overwritten with misfire or fuel trim malfunction data. Data can only be erased by clearing associated history DTCs.

RETRIEVING CODES

Note. DTCs are retrieved using TECH II or other OBD-II compatible scan tool.

  1. DTC retrieval starts with OBD-II diagnostic system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000) . Also see WIRING DIAGRAMS article for circuits and terminals referenced in testing.
  2. Turn ignition on. MIL should come on and remain on steady when ignition is on and engine is not running. When engine is started, MIL should go off. If light remains on while engine is running, a DTC is stored.
  3. If light does not come on with ignition on and engine off, inspect MIL circuit before continuing. If MIL fails to operate, see «MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE»(ref-12126-S36049612322000121100000) .
  4. To retrieve codes, install scan tool. Follow scan tool manufacturer's instruction for DTC retrieval.

CLEARING CODES

  1. After repairs are performed, clear PCM memory of all stored codes. Ensure ignition is off. To clear codes, use diagnostic scan tool CLEAR DTCS or CLEAR INFO function. Follow instructions supplied by tool manufacturer when clearing DTCs.
  2. DTCs can also be cleared by disconnecting PCM power source or negative battery cable for at least 30 seconds. However, if disconnecting battery, other memory functions (clock, radio, etc.) will need to be reset.

PCM PROGRAMMING PROCEDURE

If PCM requires replacement, PCM must be programmed using a Tech II or other OBD-II compatible scan tool. Some models may require additional equipment for reprogramming.

To reprogram PCM after it has been replaced, see PROGRAMMING .

SYSTEM CHECK

Note. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance, unless stated otherwise in test procedure.

  1. Turn ignition on with engine off. Verify Malfunction Indicator Light (MIL) is on. If MIL is on, go to next step. If MIL is not on, go to «MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE»(ref-12126-S36049612322000121100000).
  2. Turn ignition off. Install TECH II scan tool. Turn ignition on. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, verify scan tool is properly installed. If scan tool is properly installed, go to step 8.
  3. Using scan tool, command MIL OFF. If MIL turns off, go to next step. If MIL does not turn off, go to «MIL ON STEADY»(ref-12126-S02308251952000121100000).
  4. Start engine. If engine starts and continues to run, go to next step. If engine will not run, go to ENGINE CRANKS BUT WILL NOT RUN under NO START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES article.
  5. Using scan tool, check if any DTCs have been set. If any DTCs are set, go to next step. If no DTCs are set, go to step 7.
  6. If 2 or more of following DTCs are stored, go to «MULTIPLE PCM INFORMATION SENSOR DTCS SET»(ref-12126-S24178913202000121100000). P0107 P0113 P0118 P0122 P0123 If a single DTC is stored, go to appropriate DTC test under «DIAGNOSTIC TESTS»(ref-12126-S14459643112000121100000).
  7. Compare PCM data values displayed to typical engine scan data values. See appropriate SCAN TOOL DATA VALUES table under PIN VOLTAGE (VALUE) TESTS in PIN VOLTAGE CHARTS article. If values displayed are normal or close to typical values, OBD-II system check is complete. If driveability problem still exists, go to TROUBLE SHOOTING - NO CODES article. If values are not correct, go to appropriate component test in SYSTEM & COMPONENT TESTING article.
  8. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on with engine off. Check for open or short in class 2 data circuit (Orange/Black wire) between DLC terminal No. 2 and PCM harness connector terminal B13. (Scheme 21) Check for open or short in ignition feed circuit between DLC terminal No. 16 and HORN fuse. Check for open in ground circuit to DLC terminal No. 5. If problem is found, repair as necessary and return to step 2. If no problem is found, go to next step.
  9. Attempt to reprogram EEPROM. See «PROGRAMMING»(ref-12126-S29289744022000121100000). Programming PCM/EEPROM requires use of a scan tool and special manufacturer equipment. Attempt to display PCM data on scan tool. If data is now displayed, return to step 2. If data is not displayed, go to next step.
  10. Replace and reprogram PCM. After repair, return to step 2.

Scheme 21

Scheme 21
Scheme 21

SUMMARY

If no hard fault codes are present, driveability symptoms exist or intermittent codes exist, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE

  1. Perform OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000). After performing OBD-II system check, go to next step.
  2. Attempt to start engine. If engine does not start, go to step 6. If engine starts, go to next step.
  3. Check METER fuse (15-amp) located in underdash fuse/relay block. If fuse is okay, go to next step. If fuse is blown, go to step 16.
  4. Turn ignition on. Using test light connected to ground, probe ignition feed circuit for MIL at instrument cluster (Yellow wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
  5. Turn ignition off. Disconnect PCM harness connectors. Connect a jumper wire between ground and MIL control circuit at PCM harness connector terminal A13 (White/Green wire). (Scheme 21) Turn ignition on. If MIL comes on, go to step 10. If MIL does not come on, go to step 11.
  6. Check ENGINE fuse (15-amp) located in underdash fuse/relay block. Check ECM fuse (15-amp) in underhood fuse/relay block. If fuses are okay, go to next step. If fuses are blown, go to step 15.
  7. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using test light connected to ground, probe ignition feed circuits at PCM harness connector terminals E16 and F16 (Red/Blue wires). (Scheme 21) If test light illuminates, go to next step. If test light does not illuminate, go to step 12.
  8. Using test light connected to ground, probe battery feed circuit at PCM harness connector terminal A4 (Red/White wire). If test light does not illuminate, go to step 14. If test light illuminates, go to next step.
  9. Check for faulty PCM ground connections. Repair as necessary. Retest system. If connections are okay, go to next step.
  10. Check PCM harness connectors for damaged terminals. If any terminals are damaged, repair terminals as necessary. Retest system. If PCM harness connector terminals are okay, go to step 17.
  11. Check for an open circuit between MIL and PCM harness connector terminal A5. (Scheme 21) Repair as necessary. Retest system. If circuit is okay, go to step 18.
  12. Substitute PCM main relay with a known-good relay. PCM main relay is located in underhood fuse/relay block. Observe MIL. If MIL operates properly, replace PCM main relay. Retest system. If MIL still does not operate, go to next step.
  13. Repair open in ignition feed circuit (Black/Yellow wire) between PCM main relay and underdash fuse/relay block. See WIRING DIAGRAMS article. Retest system.
  14. Repair open in battery feed circuit between PCM harness connector terminal A4 (Red/White wire) and underhood fuse/relay block. See WIRING DIAGRAMS article. Retest system.
  15. Repair short to ground in PCM ignition feed circuit (Black/Yellow or Red/Blue wire) or PCM battery feed circuit (Red/White wire). See WIRING DIAGRAMS article. Retest system. Replace fuse.
  16. Repair short to ground in ignition feed circuit (Yellow wire) between instrument cluster and underdash fuse/relay block. See WIRING DIAGRAMS article. Retest system. Replace fuse.
  17. Replace and reprogram PCM. See «PROGRAMMING»(ref-12126-S29289744022000121100000). Verify proper system operation. Retest system.
  18. Check MIL driver circuit (White/Green wire) for poor connection at instrument cluster connector. Repair as necessary. Retest system. If no problem is found, diagnose problem in instrument cluster. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.

MIL ON STEADY

  1. Perform OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000). After performing OBD-II system check, go to next step.
  2. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. If MIL comes on, go to next step. If MIL does not come on, go to step 5.
  3. Turn ignition off. Disconnect instrument panel cluster connector. Check for short to ground in MIL control circuit (White/Green wire) between PCM harness connector terminal A13 and instrument panel cluster. (Scheme 21) Repair as necessary. Repeat OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000). If circuit was okay, go to next step.
  4. Replace instrument panel cluster. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Repeat OBD-II system check.
  5. Turn ignition off. Reconnect PCM harness connectors. Turn ignition on. Reprogram PCM. See «PROGRAMMING»(ref-12126-S29289744022000121100000). Using TECH II scan tool, command MIL OFF. If MIL did not go off, go to next step. If MIL did go off, repeat OBD-II system check.
  6. Replace and reprogram PCM. Repeat OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000).

MULTIPLE PCM INFORMATION SENSOR DTCS SET

  1. Perform OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000). After performing OBD-II system check, go to next step.
  2. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Check for poor connections, open or short circuits at PCM harness connector and splice. See WIRING DIAGRAMS article. If problem is found, go to next step. If circuits are okay, go to step 4.
  3. Repair poor connections, open or short circuits or weak splices as necessary. Verify system is operating properly.
  4. Check for poor connections or open in ground circuits of affected sensors. See WIRING DIAGRAMS article. If problem is found, go to next step. If connections and circuits are okay, go to step 6.
  5. Repair poor connections or open in ground circuits as necessary. Verify system is operating properly.
  6. Using DVOM, check voltage between ground and EGR pintle position sensor signal circuit at PCM harness connector terminal B7 (Yellow/Red wire). (Scheme 21) If no voltage exists, go to next step. If voltage exists, go to step 12.
  7. Using DVOM, check voltage between ground and MAP sensor signal circuit at PCM harness connector terminal F8 (Gray wire). If voltage exists, go to step 14. If no voltage exists, go to next step.
  8. Using DVOM, check voltage between ground and TP sensor signal circuit at PCM harness connector terminal E8 (Blue wire). (Scheme 21) If no voltage exists, go to next step. If voltage exists, go to step 15.
  9. Using DVOM, check voltage between ground and IAT sensor signal circuit at PCM harness connector terminal B8 (Yellow/Green wire). If no voltage exists, go to next step. If any voltage exists, go to step 16.
  10. Using DVOM, check voltage between ground and ECT sensor signal circuit at PCM harness connector terminal E9 (Blue/Red wire). (Scheme 21) If no voltage exists, go to next step. If voltage exists, go to step 17.
  11. Using DVOM, check voltage between ground and A/C pressure sensor circuit at PCM harness connector terminal B9 (Green wire). If no voltage exists, go to next step. If voltage does exist, go to step 18.
  12. Disconnect EGR valve. Using DVOM, check voltage between ground and EGR pintle position sensor signal circuit at PCM harness connector terminal B7 (Yellow/Red wire). (Scheme 21) If no voltage exists, go to next step. If voltage exists, go to step 19.
  13. Replace EGR valve. Verify system is operating properly.
  14. Repair short to voltage in Gray wire between PCM harness connector terminal F8 and MAP sensor. (Scheme 21)and see scheme 2.
  15. Repair short to voltage in Blue wire between PCM harness connector terminal E8 and TP sensor. (Scheme 21)and see scheme 5.
  16. Repair short to voltage in Yellow/Green wire between PCM harness connector terminal B8 and IAT sensor. (Scheme 21)and see scheme 3.
  17. Repair short to voltage in Blue/Red wire between PCM harness connector terminal E9 and ECT sensor. (Scheme 21)and see scheme 4.
  18. Repair short to voltage in Green wire between PCM harness connector terminal B9 and A/C pressure sensor. (Scheme 21)and see scheme 17.
  19. Repair short to voltage in Yellow/Red wire between PCM harness connector terminal B7 and EGR valve. (Scheme 21)and see scheme 11.
  20. Replace and reprogram PCM. See «PROGRAMMING»(ref-12126-S29289744022000121100000). Repeat OBD-II system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-12126-S06180705522001050100000).

PROGRAMMING

Note. Refer to latest Isuzu Technical Communication System (ITCS) Information for reprogramming or flashing procedures.

EEPROM PROGRAMMING PROCEDURE

Connect scan tool and retrieve information from PCM. Turn ignition off. Ensure battery is fully charged. Download latest program and calibration from ITCS. Turn ignition on. Reconnect scan tool and program PCM. Start engine and allow to run for at least one minute. Check for DTCs. If PCM does not program, check all PCM connections and retry. If PCM still can not be reprogrammed, replace PCM.

TOOTH ERROR CORRECTION LEARN PROCEDURE

  1. Ensure all fluid levels are normal, engine is at operation temperature, and no camshaft or crankshaft DTCs are present before performing this procedure. Place vehicle in PARK or Neutral. Block drive wheels. Turn off all accessories.
  2. Using scan tool, enable Tooth Error Correction procedure. This will limit RPM. Depress and hold brake pedal. Depress and hold throttle fully (100 percent) until correction is learned or number of attempts to learn are exceeded. Release throttle as soon as engine speed decreases. After throttle is released, RPM will no longer be limited. Do not depress throttle fully after releasing.

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