Engine Controls - Tests W/codes - Introduction: Other Isuzu Amigo II

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 the 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 will 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.
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. If the fault is not detected during 3 consecutive driving cycles, the MIL light will be turned off.
3. Type C This is a non-emission related type 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, will not turn on service light, but will store DTCs for present faults.

PRELIMINARY CHECK

Perform On-Board Diagnostic 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 (code) charts. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION . 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 TESTS W/O CODES article.

FREEZE-FRAME DATA

Engine operating conditions which cause MIL to illuminate are recorded in PCM memory. This record, called freeze frame data, is a snap shot of the driving conditions that are recorded on the 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. The data can only be erased by clearing associated history DTCs.

RETRIEVING CODES

Note. Diagnostic Trouble Codes (DTCs) are retrieved using Tech 2 or other OBD II compatible scan tool.

1. Diagnostic Trouble Code (DTC) retrieval starts with OBD-II diagnostic system check. See «ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK»(ref-16364-S24901877752000122900000) . Also see appropriate «WIRING DIAGRAMS»(ref-16366) article for circuits and terminals referenced in testing.
2. Turn ignition on. MIL should come on and remain 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 «BASIC TESTING»(ref-16362) article.
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 the PCM power source or negative battery cable for at least 30 seconds. However, if disconnecting battery, remember that other memory functions (clock, radio, etc.) will need to be reset.

PCM REPROGRAM PROCEDURE

If PCM requires replacement PCM must be reprogrammed using a Tech 2 or other OBD-II compatible scan tool. Some models may require additional equipment for EEPROM programming.

AMIGO, RODEO & PASSPORT (2.2L & 3.2L)

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 «BASIC TESTING»(ref-16362) article.
2. Turn ignition off. Install Tech 2 scan tool. Follow manufacturer's instructions for scan tool operation. 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 «BASIC TESTING»(ref-16362) article.
4. Start engine. If engine starts and continues to run, go to next step. If engine will not run, go to «BASIC TESTING»(ref-16362) 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. Are 2 or more of the following DTCs stored? P0107 P0113 P0118 P0122 P0123 If 2 or more of these codes are stored, go to «BASIC TESTING»(ref-16362) article. If a single DTC is stored, go to appropriate DTC under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below: For SLX, Amigo, Rodeo, Trooper and Passport 2.2L, see «TESTS W/CODES (2.2L)»(ref-16367) article. For Hombre 2.2L, see «TESTS W/CODES (2.2L)»(ref-16368) article. For SLX, Amigo, Rodeo, Trooper and Passport 3.2L and 3.5L, see «TESTS W/CODES - 3.2L & 3.5L»(ref-16369) article.
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»(ref-16370) article. If values displayed are normal or close to typical values, OBD-II system check is complete. If driveability problem still exists, go to «TESTS W/O CODES»(ref-16365) article. If values are not correct, go to «SYSTEM & COMPONENT TESTS»(ref-16371) article.
8. Turn ignition off. Disconnect PCM connectors. Turn ignition on with engine off. Check for open or short in class 2 data circuit (Orange/Black wire) between Data Link Connector (DLC) terminal No. 2 and PCM 36-pin Red connector terminal B13. Also check for open or short in ignition feed circuit (Green/Yellow wire) between DLC terminal No. 16 and dash fuse box. Also check for open in ground circuit (Black/Blue wire) to DLC terminal No. 4. If no problems are found, repair as necessary and return to step 2). If no problems are found, go to next step.
9. Attempt to reprogram EEPROM. See «COMPUTER RELEARN PROCEDURES»(ref-12612) article in GENERAL INFORMATION section. 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 PCM. Program PCM. See «COMPUTER RELEARN PROCEDURES»(ref-12612) article in GENERAL INFORMATION section. After repair, recheck system operation.

HOMBRE 2.2L

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. If Malfunction Indicator Light (MIL) illuminates, go to next step. If MIL does not function properly, go to MIL INOPERATIVE.
2. Turn ignition off. Install Tech 2 scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, see «BASIC TESTING»(ref-16362) article.
3. Using scan tool, command MIL to turn off. If MIL turns off, go to next step. If MIL does not turn off, go to MIL ON STEADY.
4. Using scan tool, check if any LAST TEST FAIL, HISTORY or MIL REQUEST DTC(s) are stored. If DTC(s) exist, go to next step. If DTC(s) do not exist, go to step 6).
5. Using scan tool, store FREEZE FRAME and FAILURE RECORDS data. Diagnose any stored DTC. See «TESTS W/CODE - INTRODUCTION»(ref-16364) and appropriate TESTS W/CODES articles below: For SLX, Amigo, Rodeo, Trooper and Passport 2.2L, see «TESTS W/CODES (2.2L)»(ref-16367) article. For Hombre 2.2L, see «TESTS W/CODES (2.2L)»(ref-16368) article. For SLX, Amigo, Rodeo, Trooper and Passport 3.2L and 3.5L, see «TESTS W/CODES - 3.2L & 3.5L»(ref-16369) article.
6. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start, or starts and dies, see «BASIC TESTING»(ref-16362) article.
7. Turn ignition on with engine off. Check Engine Coolant Temperature (ECT) and Throttle Position (TP) sensors for proper operation. Start and warm engine to normal operating temperature. Check ECT sensor, MAP sensor, O2 sensors, and IAC valve for proper operation. Compare scan tool engine data with actual control system data values. If value is within limits, see «TESTS W/O CODES»(ref-16365) article. If value is not within limits, go to «SYSTEM & COMPONENT TESTS»(ref-16371) article.

HOMBRE 4.3L

Note. Powertrain Control Module (PCM) may also be referred to as VCM.

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 off. Install Tech 2 scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. If scan tool displays VCM data, go to next step. If scan tool does not display VCM data, go to «BASIC TESTING»(ref-16362) article.
2. Turn ignition on with engine off. Observe Malfunction Indicator Light (MIL). If MIL illuminates, go to next step. If MIL does not illuminate, go to MALFUNCTION INDICATOR LIGHT (MIL) INOPERATIVE.
3. Using scan tool, select DIAGNOSTIC SYSTEM CHECK. Monitor SERIAL DATA CLASS II messages. If all modules connected to Serial Data Class II circuits are communicating, go to next step. If any module(s) is not communicating, recheck all harness connections and scan tool installation. Repair as necessary.
4. Using scan tool, check for any class II DTCs. If no DTCs are stored, go to next step. If any DTCs are stored, go to «DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION»(ref-16364-S09266609502000122900000) . Proceed to appropriate DTC test under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below: For SLX, Amigo, Rodeo, Trooper and Passport 2.2L, see «TESTS W/CODES (2.2L)»(ref-16367) article. For Hombre 2.2L, see «TESTS W/CODES (2.2L)»(ref-16368) article. For SLX, Amigo, Rodeo, Trooper and Passport 3.2L and 3.5L, see «TESTS W/CODES - 3.2L & 3.5L»(ref-16369) article.
5. Using scan tool, command MIL to turn off. If MIL turns off, go to next step. If MIL does not turn off, see «BASIC TESTING»(ref-16362) article.
6. Crank engine for 10 seconds. If engine starts, go to next step. If engine does not start, see «BASIC TESTING»(ref-16362) article.
7. Using scan tool, retrieve any stored DTCs. If DTC P1626 or P1631 is retrieved, see appropriate DTC test under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below: For SLX, Amigo, Rodeo, Trooper and Passport 2.2L, see «TESTS W/CODES (2.2L)»(ref-16367) article. For Hombre 2.2L, see «TESTS W/CODES (2.2L)»(ref-16368) article. For SLX, Amigo, Rodeo, Trooper and Passport 3.2L and 3.5L, see «TESTS W/CODES - 3.2L & 3.5L»(ref-16369) article. If indicated DTCs are not stored, see «BASIC TESTING»(ref-16362) article.
8. Using scan tool, observe DTC status for MIL REQUEST, FAIL THIS IGN, LAST TST FAIL and HISTORY. If any DTC(s) is stored, save freeze frame and fail record information using scan tool CAPTURE INFO feature. If any of these DTC status are present, refer to affected DTC to diagnose problem. If DTC(s) are not present, go to next step.
9. Turn ignition on with engine off. Using scan tool, check Engine Coolant Temperature (ECT) sensor values. Start engine and warm to normal operating temperature. Compare readings with scan tool data list. If value is within typical range, go to next step. If value is not within limits, go to «SYSTEM & COMPONENT TESTS»(ref-16371) article.
10. If there is still a driveability complaint, see «TESTS W/O CODES»(ref-16365) article. If no driveability problem exists, system is functioning properly.

TROOPER & SLX 3.5L

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 «BASIC TESTING»(ref-16362) article.
2. Turn ignition off. Install Tech 2 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 «BASIC TESTING»(ref-16362) article.
4. Start engine. If engine starts and continues to run, go to next step. If engine will not run, go to «BASIC TESTING»(ref-16362) 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. Are 2 or more of the following DTC(s) stored? P0107 P0108 P0113 P0118 P0122 P0123 P0712 P1392 P1406 If 2 or more of these codes are stored, go to «BASIC TESTING»(ref-16362) article. If a single DTC is stored, go to appropriate DTC test under DIAGNOSTIC TESTS in appropriate TESTS W/CODES articles below: For SLX, Amigo, Rodeo, Trooper and Passport 2.2L, see «TESTS W/CODES (2.2L)»(ref-16367) article. For Hombre 2.2L, see «TESTS W/CODES (2.2L)»(ref-16368) article. For SLX, Amigo, Rodeo, Trooper and Passport 3.2L and 3.5L, see «TESTS W/CODES - 3.2L & 3.5L»(ref-16369) article.
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»(ref-16370) article. If values displayed are normal or close to typical values, OBD-II system check is complete. If driveability problem still exists, go to «TESTS W/O CODES»(ref-16365) article. If values are not correct, go to «SYSTEM & COMPONENT TESTS»(ref-16371) article.
8. Turn ignition off. Disconnect PCM connectors. Turn ignition on with engine off. Check for open or short in class 2 data circuit (Orange/Green wire) between Data Link Connector (DLC) terminal No. 2 and PCM 32-pin connector C-1, terminal B13. Also check for open or short in ignition feed circuit (Green/White wire) between DLC terminal No. 16 and dash fuse box. Also check for open in ground circuit (Black wire) to DLC terminal No. 4. 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. Programming PCM/EEPROM requires the 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 PCM. Program PCM. After repair, return to step 2).

SUMMARY

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