Continuous Memory Code 18 Or 212 (IDM Missing)
- Ensure SPARK OUTPUT CHECK has been performed. See NO-START DIAGNOSIS in BASIC TESTING article in the ENGINE PERFORMANCE Section. Turn ignition on.
- Turn ignition off. Connect DI Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. See Figure. Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position.
- Apply DI overlay on breakout box. Disconnect PCM. For CCD (Black module) equipped systems, go to step 6). For non-CCD (Gray module) equipped systems, set DVOM on DC scale. Disconnect ignition coil wiring harness connector. Turn ignition on.
- Measure voltage between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If voltage is greater than 5.0 volts DC, repair IDM circuit short to power between PCM and IDM 22-k/ohm resistor. If voltage is less than 5.0 volts DC, turn ignition off.
- Measure resistance between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If resistance is less than 10 k/ohms, repair IDM circuit short to ground between PCM and IDM 22-k/ohm resistor. If resistance is 10 k/ohms or more, measure resistance between J4 (COIL-) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If resistance is not 20-24 k/ohms, repair open or shorted IDM circuit.
- Turn ignition off. Set DVOM on AC scale. Crank engine while measuring voltage between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If voltage is greater than 1.0 volt AC, replace PCM. If voltage is not greater than 1.0 volt AC, turn ignition off.
- Disconnect diagnostic connector from ICM. Leave ICM wiring harness connector connected to diagnostic cable. Set DVOM on DC scale. Turn ignition on. Measure voltage between J7 (B-) and J23 (IDM). If voltage is less than 0.5 volt, repair short to power in IDM circuit between PCM and ICM wiring harness connector.
- If voltage is 0.5 volt or more, turn ignition off. Measure resistance between J7 (B-) and J23 (IDM). If resistance is less than 10 k/ohms, repair short to ground in IDM circuit between PCM and ICM wiring harness connector. If resistance is greater than 10 k/ohms, measure resistance between J23 (IDM) and terminal No. 4 of PCM wiring harness connector. If resistance is 5 ohms or less, replace ICM. If resistance is greater than 5 ohms, repair open in IDM circuit between PCM and ICM wiring harness connector.