Idle Speed/Throttle Actuator - Electronic: Testing and Inspection

DME Control Unit Harness Connector:

Injection Electronics. Wiring Diagram:

1. With the ignition switch OFF, remove the DME control unit harness connector X1500 (control unit is located in the E-Box) see COMPONENT LOCATIONS.
2. Connect a fused jumper between terminal 36 of the DME control unit harness connector and ground.
3. Turn the ignition switch to the run (ON) position.
4. With a fused jumper, MOMENTARILY ground terminal 4 of the DME control unit harness connector.

^ Idle control valve should run. Remove fused jumper from terminal 4.

5. With a fused jumper, MOMENTARILY ground terminal 22 of the DME control unit harness connector.

^ Idle control valve should run. Remove fused jumper from terminal 22.

^ If idle valve runs continue with step 6. If idle control valve does not run, remove the fused jumper and go to step 7.

6. With the ignition OFF, remove the fused jumper from terminal 36 and reconnect the DME control unit harness connector. Start the engine and warm it up to normal operating temperature while varying the load conditions.

^ If the "Check Engine" light illuminates and a fault code 1262 is present check gray wire to terminal 15 of X1500 for a short to ground. If a short is present repair or replace as necessary.

^ If no defects are present, an abrupt drop in engine speed might have caused fault code 1262 to set.

7. With the ignition OFF, remove the idle control valve harness connector X1514.

^ Check between terminal 4 of the DME control unit and terminal 3 of the idle control unit for a short to ground or battery power.
^ Check between terminal 22 of the DME control unit and terminal 1 of the idle control unit for a short to ground or battery power. If either condition is present repair or replace the affected wiring.

Idle Control Valve:

8. Check resistance between

^ Terminal 1 and terminal 2 of the idle valve.

Expected result: = 18 to 22 ohms.

If not: replace the idle valve.

^ Terminal 2 and terminal 3 of the idle valve.

Expected result: = 18 to 22 ohms.

If not: replace the idle valve

9. With the ignition OFF, remove the fused jumper from terminal 36 of the DME control unit harness and reconnect to the DME control unit. With the ignition switch in the run (ON) position make the following voltage measurement at terminal X1514 (female half).

^ Red/white wire (terminal 2) and ground.

Expected result: = battery voltage.

If not: check wire to main relay for an open

10. If all measurements are OK replace the DME control unit with a known good part.