Isuzu OBD / OBD2 Codes

• Accessing Codes
  • Except I-MARK
  • I-MARK 84-85
  • 86-87 Impulse
  • 88-89
  • Throttle Body Fuel Injection
  • Multi-Port Fuel Injection
    • Amigo,Trooper II , Rodeo & Pickup
    • Stylus & Impulse
    • Oasis
• Clearing Codes
  • Carb Models
  • Injected Models
• Isuzu Diagnostic Trouble Codes
• Codes by Model / Year
• Questions & Answers

NOTE: 96 & later are OBD2 systems and require a scanner. For an OBD2 code list, please see our Isuzu code list or the appropriate generic list.

Isuzu: Accessing Trouble Codes

Except I-MARK

I-MARK 84-85

• Connect male and female test leads taped into wire harness near ECM.
• After leads are connected, the “Check Engine” lamp will flash the trouble codes.
• The DTC’s are indicated by the flashing CEL.
• FLASH, FLASH, pause, FLASH, FLASH, FLASH = Code 23.
• If only one diagnostic trouble code is stored, the DTC will repeat continuously until test leads are disconnected.
• If more than one diagnostic trouble code is stored, each DTC will repeat three times, starting with the lowest, then proceed to the next DTC. After all DTC’s have been displayed, the pattern will repeat.

86-87 Impulse

Entering Diagnostic Mode

1. Turn ignition on. “CHECK ENGINE” lamp should light.
2. Locate diagnostic leads.
3. Connect diagnostic terminal leads together.
4. If any trouble codes are stored in ECU memory, the “CHECK ENGINE” lamp will flash 2-digit codes.
5. The trouble codes will be displayed from lowest to highest numbered code. Each code is repeated three times before the next code sequence is displayed. The trouble codes will be repeated as long as the diagnostic terminals are connected and the ignition is on.
6. Remove fuse No.4 to clear memory.

88-89

• A three-terminal connector (ALDL), located near the ECM connector, is used to actuate the Engine Control Module (ECM) trouble code memory within the module.
• Two terminals (A and C) of this connector are used to activate the diagnostic trouble code system in the ECM.
• With the ignition switch turned On, engine Off, connect a jumper wire between terminals A and C.
• The “Check Engine” lamp will begin by flashing a DTC 12. DTC 12 = flash, pause, flash, flash. There will be a longer pause and a code 12 will repeat two more times. This code indicates the self-diagnostic system is operating.
• The cycle will then repeat until the engine is started or the ignition is switched Off. In most cases, DTC’s will be checked with the engine running since no DTC’s other than DTC 12 or 51 will be present without the engine running.
• Remove jumper wire from ALDL connector before starting engine.
• Reconnect jumper wire after engine is running.

Throttle Body Fuel Injection

• The ECM test connection is located under the center console.
• A built-in, self diagnostic system will identify problems in the throttle body fuel injection system.
• When a problem is detected, the diagnostic system will illuminate the “Check Engine” light.
• When the engine is started, the Check Engine light should turn off.
• If the light remains lit, the self diagnostic has detected a problem.
• To determine where the problem exists, ground the “Test” terminal of the connector with the ignition On, engine Off and watch the check engine light. Each DTC will flash three times (lowest to highest).

Multi-Port Fuel Injection

Amigo,Trooper II , Rodeo & Pickup

• On Rodeo, Amigo, and Pickup (except 1993-95 models W/3.2L engine), connect the single wire diagnostic leads located behind the left hand kick panel together.
• On Trooper models to 1991, the single wire diagnostic connectors are located under the center console.
• On 1992-95 Trooper & 1993-95 Rodeo models W/3.2L engine, connect a jumper wire between data link connector terminals 1 and 3.
• On 1992-95 Trooper models the data link connector is located behind the lower front of the instrument panel.
• On 1993-95 Rodeo models W/3.2 engine, the data link is located under the left hand side of the instrument panel.
• On all models, turn the ignition switch to the On position. At this point, the “Check Engine” light should flash.

Stylus & Impulse

• A white three terminal ALDL connector located behind the passenger side kick panel.
• The ECM has a battery voltage line to the ALDL connector.
• Using a jumper wire, connect this terminal to ground.
• The ECM will then toggle the “Check Engine” light to flash any trouble codes stored in the memory of the ECM.
• If no DTC’s are stored, the light will flash DTC 12.
• If a trouble code exist the lowest number DTC will flash first.
• Each DTC will flash three times.

Oasis

• If the malfunction indicator/check engine lamp remains lit or comes on while the engine is operating, the ECM has detected a malfunction and has stored a trouble code in its memory.
• To access the trouble code memory, connect an OBD II scan tool to the 16-pin DLC connector located behind the right-hand side of the front console.

Clearing Trouble Codes

Carb Models

Trouble codes can be cleared by removing voltage to the ECM for 10 seconds. After a fault has been corrected, remove the ECM fuse or disconnect battery cables for 10 seconds.

Injected Models

Except Oasis

To prevent damage to the ECM when disconnecting the battery ground cable, ensure the ignition key is in the Off position. Disconnecting the battery ground cable for 30 seconds or longer will clear all stored trouble codes from the ECM.

Oasis

Trouble codes should be cleared from the ECM (ECU) by either turning off the ignition switch and removing the back-up radio (7.5A) fuse from the under hood fuse/relay box for 10 seconds, or by using the OBD II scan tool to clear the ECM’s memory.

Isuzu Diagnostic Trouble Codes

Isuzu Codes by Model / Year