Isuzu Amigo S 1992 - 1991-92 ENGINE PERFORMANCE Self-Diagnostics - Amigo & Pickup - 2.3L Carbureted
Isuzu Amigo S 1992 - INTRODUCTION
If no faults were found while performing appropriate BASIC TESTING article in the ENGINE PERFORMANCE Section proceed with self-diagnostics. If no fault codes or only pass codes are present after entering self-diagnostics, proceed to appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e. ROUGH IDLE, NO START, etc.).
Isuzu Amigo S 1992 - SELF-DIAGNOSTIC SYSTEM HARD FAILURES
Hard failures cause CHECK ENGINE light to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, determine cause of malfunction using diagnostic (code) charts. If a sensor fails, Electronic Control Module (ECM) will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.
Isuzu Amigo S 1992 - INTERMITTENT FAILURES
Intermittent failures may cause CHECK ENGINE light to flicker or illuminate and go out after intermittent fault goes away. However, the corresponding trouble code will be stored in ECM memory. If related fault does not reoccur within a certain time frame, related trouble code will be erased from ECM memory. Intermittent failures can be caused by a faulty sensor, connector or wiring. See INTERMITTENTS in appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE Section.
Fig. 1: Isuzu Amigo S 1992 - Component Locations - Locating ECM & Diagnostic Connector
Isuzu Amigo S 1992 - RETRIEVING CODES
- Code retrieval starts with the DIAGNOSTIC CIRCUIT CHECK. The CHECK ENGINE light comes on when ignition is on and engine is not running. When engine starts, CHECK ENGINE light should go off. If light remains on while engine is running, a trouble code is present.
- If light did not come on with key on and engine off, inspect CHECK ENGINE light circuit before continuing. If CHECK ENGINE light fails to operate, see DIAGNOSTIC CIRCUIT CHECK. Circuit checks are located within code charts.
- To retrieve codes, install jumper wire between White and Black wires of ALDL diagnostic connector, located behind left kick panel near ECM. See Fig. 1 .
NOTE: Diagnostic connector may also be referred to as ALDL test lead. - Turn ignition on and count number of flashes from CHECK ENGINE light. A Code 12 will be a flash, pause and flash, flash. A long pause will occur. Code 12 will repeat 3 times. See Fig. 2 . Each additional code will flash 3 times, starting with lowest number code to the highest number code. Once all codes are displayed, codes will be repeated.
- If system is operating properly (with no codes), a Code 12 should exist with ignition on and engine off. This indicates diagnostic system is working. Remove jumper wire from ALDL diagnostic connector after codes are retrieved.
Fig. 2: Isuzu Amigo S 1992 - Component Locations - Code Display (Typical)
Isuzu Amigo S 1992 - CLEARING TROUBLE CODES
CAUTION: Ensure ignition is off when disconnecting or reconnecting power to ECM.
- After performing repairs, clear ECM memory of stored trouble codes. To clear memory, turn ignition off. Remove 60-amp MAIN fuse from fuse block, located in left front corner of engine compartment, for at least 10 seconds. Replace fuse.
- Trouble codes can also be cleared by disconnecting negative battery cable. However, other memory functions (clock, radio, etc.) will then require resetting.
NOTE: Codes will also erase if problem does not reoccur within 50 engine starts.
Isuzu Amigo S 1992 ECM LOCATIONS
Model Location Amigo & Pickup On left kick panel
Isuzu Amigo S 1992 - CODE CHARTS TROUBLE CODE IDENTIFICATION
Isuzu Amigo S 1992 TROUBLE CODE IDENTIFICATION
Code No. System Affected Probable Cause 12 (1) Ignition Ref. Signal Dist. or Circuit, ECM 13 (2) O2 Sensor Sensor/Circuit, ECM 14 (3) Shorted Coolant Temp. Sensor Signal Sensor/Circuit, ECM 15 (4) Open Coolant Temp. Sensor Signal Sensor/Circuit, ECM 21 (5) Idle (Vacuum) Switch & MAP Sensor Switch/Circuit, ECM 22 (6) Fuel-Cut Solenoid Relay/Circuit, ECM 23 Duty (Mixture Control) Solenoid Circuit Solenoid Circuit, ECM 25 AIR Management Valve VSV/Valve Circuit, ECM 26 Canister Purge VSV VSV/Valve Circuit, ECM 27 Canister Purge VSV VSV/Valve Circuit, ECM 31 (2) (7) Ignition Ref. Signal Wiring Circuit, ECM 32 EGR System EGR Valve, Thermal Vac. Valve or Backpressure Transducer 34 EGR Gas Temp. Sensor Sensor/Circuit, ECM 44 (2) (8) O2 Sensor (Lean) Mixture Control Solenoid, O2 Sensor, ECM 45 (2) (9) O2 Sensor (Rich) Mixture Control Solenoid, O2 Sensor, ECM 51 Fuel-Cut Solenoid Solenoid/Circuit, ECM 52 Faulty ECM RAM ECM 53 AIR Management Valve Valve or ECM 54 Mixture Control Solenoid Solenoid/Circuit, ECM 55 Faulty ECM ECM
(1) Code 12 is a normal response to key on and engine off with ALDL test lead installed.
(2) Requires engine operation at part throttle under load for up to 5 minutes after engine reaches normal operating temperature to set code.
(3) Engine must be running at least 2 minutes before code will be set.
(4) Engine must be running at least 5 minutes before code will be set.
(5) Code will set if one of following conditions exist: Engine speed is 200-1000 RPM and vacuum applied to MAP sensor is more than 20 in. Hg for 5 seconds; Idle switch is off and vacuum applied to MAP sensor is less than 4 in. Hg for 5 seconds.; Engine speed is greater than 1500 RPM and vacuum applied to MAP sensor is 16-18 in. Hg and idle switch is on for 5 seconds.
(6) Engine must be decelerating and engine speed greater than 2000 RPM before code will be set.
(7) No reference signal to ECM after 10 seconds at part throttle under load. Code will be stored in memory.
(8) Engine speed must be less than 2500 RPM and exist for 5 seconds after fuel-cut recovery. Code will set except when vacuum reading to MAP sensor is less than 23 in. Hg, Code 13 or 21 is stored, or coolant temperature is greater than 302?F (150?C).
(9) Engine speed must be less than 2500 RPM with vehicle speed of 12-50 MPH for more than 30 seconds after canister purge. Code will set except when vacuum reading to MAP sensor is less than 23 in. Hg, Code 13 or 21 is stored, coolant temperature is greater than 302?F (150?C) or under high altitude conditions greater than 8000 ft. (2434 meters).
Isuzu Amigo S 1992 - ECU TERMINAL IDENTIFICATION
CAUTION: Perform all voltage measurements with ECU harness connector installed.
Isuzu Amigo S 1992 - DIAGNOSTIC CIRCUIT CHECK
Fig. 5: Isuzu Amigo S 1992 - Component Locations - Diagnostic Circuit Check
Isuzu Amigo S 1992 - TEST NO. 1 - CHECK ENGINE LIGHT INOPERATIVE
Isuzu Amigo S 1992 - TEST NO. 2 - WILL NOT FLASH CODE NO. 12
Fig. 8: Isuzu Amigo S 1992 - Component Locations - Test No. 2 Flow Chart, Won't Flash Code No. 12
Isuzu Amigo S 1992 - CODE 12 - IGNITION REFERENCE SIGNAL
NOTE: To check ignition system components, see IGNITION SYSTEM in appropriate I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
Fig. 9: Isuzu Amigo S 1992 - Component Locations - Code No. 12 Schematic, Ignition Reference Signal
Isuzu Amigo S 1992 - CODE 13 - OXYGEN SENSOR CIRCUIT
NOTE: If Codes 13 and 23 exist, start with Code 23.
Fig. 11: Isuzu Amigo S 1992 - Component Locations - Code No. 13 Schematic, Oxygen Sensor Circuit
Fig. 12: Isuzu Amigo S 1992 - Component Locations - Code No. 13 Flow Chart, Oxygen Sensor Circuit
Isuzu Amigo S 1992 - CODE 14 - SHORTED COOLANT TEMPERATURE SENSOR SIGNAL
Isuzu Amigo S 1992 - CODE 15 - OPEN COOLANT TEMPERATURE SENSOR SIGNAL
Isuzu Amigo S 1992 - CODE 21 - IDLE (VACUUM) SWITCH & MAP SENSOR
NOTE: If Codes 21 and 23 exist, start with Code 23.
Isuzu Amigo S 1992 - CODE 22 & 51 - FUEL-CUT SOLENOID CIRCUIT
Isuzu Amigo S 1992 - CODE 23 & 54 - DUTY (MIXTURE CONTROL) SOLENOID CIRCUIT
Fig. 21: Isuzu Amigo S 1992 - Component Locations - Code No. 23, 54 Schematic, Duty Solenoid Circuit
Isuzu Amigo S 1992 - CODE 25 & 53 - AIR MANAGEMENT VALVE CIRCUIT
Isuzu Amigo S 1992 - CODE 26 & 27 - CANISTER PURGE VSV CIRCUIT
Isuzu Amigo S 1992 - CODE 31 - IGNITION REFERENCE SIGNAL
Fig. 27: Isuzu Amigo S 1992 - Component Locations - Code No. 31 Schematic, Ignition Reference Signal
Isuzu Amigo S 1992 - CODE 32 - EGR SYSTEM MALFUNCTION Specified Reappearance Pattern
- Run engine at idle condition, at normal operating temperature.
- Keep at idle for more than 10 seconds, with vehicle stopped
- Drive vehicle at just over 10 MPH. Accelerate quickly to more than 30 MPH (must reach 30 MPH within 10 seconds of starting acceleration).
- Within 30 seconds, decelerate safely to a complete stop. See Fig. 29 .
- Repeat above procedure 2) through 4) several times.
Fig. 29: Isuzu Amigo S 1992 - Component Locations - Code No. 32 Acceleration Chart
Fig. 31: Isuzu Amigo S 1992 - Component Locations - Code No. 32 Flow Chart, EGR System Malfunction
Isuzu Amigo S 1992 - CODE 34 - EGR GAS TEMPERATURE SENSOR
Isuzu Amigo S 1992 EGR GAS TEMP SENSOR RESISTANCE
Temperature ?C (?F) Resistance Ohms 0 (32) 28000 20 (68) 12100 40 (109) 5800 80 (176) 1700
Fig. 32: Isuzu Amigo S 1992 - Component Locations - Code No. 34 Schematic, EGR Gas Temp. Sensor
Isuzu Amigo S 1992 - CODE 44 - OXYGEN SENSOR-LEAN FUEL MIXTURE
- Disconnect oxygen sensor connector. With ignition ON and engine stopped, check for repeated clicks from duty solenoid.
- If there are repeated clicks, repair carburetor. If no repeated clicks are heard, replace duty solenoid.
Isuzu Amigo S 1992 - CODE 45 - OXYGEN SENSOR-RICH FUEL MIXTURE
NOTE: A restricted air cleaner can cause a Code 45.
- Disconnect oxygen sensor connector. With ignition ON and engine stopped, check for repeated clicks from duty solenoid.
- If there are repeated clicks, repair carburetor. If no repeated clicks are heard, replace duty solenoid.
Isuzu Amigo S 1992 - CODE 51 - FUEL-CUT SOLENOID CIRCUIT
See Code No. 22.
Isuzu Amigo S 1992 - CODE 52 - FAULTY ECM RAM
Fig. 41: Isuzu Amigo S 1992 - Component Locations - Code No. 52 Flow Chart, Faulty ECM Ram
Isuzu Amigo S 1992 - CODE 53 - AIR SWITCHING VALVE VSV OR ECM
See Code No. 25.
Isuzu Amigo S 1992 - CODE 54 - DUTY (MIXTURE CONTROL) SOLENOID CIRCUIT
See Code No. 23.
Isuzu Amigo S 1992 - CODE 55 - FAULTY ECM
Fig. 42: Isuzu Amigo S 1992 - Component Locations - Code No. 55 Flow Chart, Faulty ECM
Isuzu Amigo S 1992 - SUMMARY
If no hard fault codes (or only pass codes) are present, driveability symptoms exist or intermittent codes exist, proceed to appropriate TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e. ROUGH IDLE, NO START, etc.), or intermittent diagnosis procedures.