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Pinpoint Test B: Code 212

  1. Verify Erratic Starting  If vehicle is hard to start (requires more than one attempt to start and/or cranking speed is erratic), go to step 2). If vehicle is not hard to start, go to step 4).
  2. Check CID Signal At ICM  Turn ignition off. Install diagnostic cable. Connect diagnostic cable to breakout box. Connect diagnostic cable negative and positive leads to battery. Use 3.0L/3.2L/3.8L overlay. Bump engine using starter (10 revolutions) while measuring voltage between J51 (CID D) and J60 (BAT-). If DVOM switches between less than 2 volts DC and greater than 8 volts DC, replace ICM. If DVOM does not switch between less than 2 volts and greater than 8 volts, go to step 3).
  3. Check CID Signal At CMP Sensor  Turn ignition off. Install CMP sensor tee. Bump engine using starter (short engagements) while measuring voltage between J21 (CID S) and J60 (BAT-). If DVOM does not switch between low voltage and high voltage, replace CMP sensor. If DVOM switches between low voltage and high voltage, repair open in CID circuit.
  4. Check ICM IDM Signal Output  Turn ignition off. Install diagnostic cable module tee (terminals No. 7-12) to ICM. Connect diagnostic cable to breakout box. Connect diagnostic cable negative and positive leads to battery. Use 3.0L/3.2L/3.8L overlay. Set DVOM on 20-volt AC range. Start engine. Measure voltage between J4 (IDM I) and J60 (BAT-). If voltage is greater than 1.0 volt AC, go to step 5). If voltage is 1.0 volt AC or less, go to step 6).
  5. Check IDM Circuit Continuity  Turn ignition off. Disconnect PCM. Connect second breakout box to PCM wiring harness connector. Measure resistance between J4 (IDM I) of first breakout box and J4 (IDM I) of second breakout box. If resistance is 5 ohms or less, replace PCM. If resistance is greater than 5 ohms, repair open IDM circuit between ICM and PCM.
  6. Check PCM For IDM Circuit Fault  Leave ignition off and PCM disconnected. Bump engine using starter (10 revolutions) while measuring voltage between J4 (IDM I) and J60 (BAT-) at breakout box. If DVOM switches between low voltage and high voltage, replace PCM. If DVOM does not switch between low voltage and high voltage, go to step 7).
  7. Check IDM For Short To Power  Turn ignition off. Disconnect diagnostic cable connector from ICM (terminals No. 7-12). Leave diagnostic cable connected to wiring harness. Turn ignition on. Measure voltage between J4 (IDM I) and J60 (BAT-). If voltage is greater than 6 volts DC, repair IDM circuit short to power between PCM and ICM. If voltage is 5 volts DC or less, go to step 8).
  8. Check IDM For Short To Ground  With ignition off, measure resistance between J4 (IDM I) and J60 (BAT-). If resistance is greater than 10 k/ohms, replace ICM. If resistance is less than 10 k/ohms, repair IDM circuit short to ground between PCM and ICM.


  1. Check For IDM Signal At ICM  With ignition off, connect diagnostic cable to breakout box and ICM. DO NOT connect CKP sensor tee. Use EI (High Data Rate) 4 overlay on breakout box. Connect diagnostic cable negative and positive leads to battery. Set diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM on AC voltage scale. Start engine and measure voltage between J30 (diagnostic cable IDM DETECTOR) and J7 (B-) at breakout box. If AC voltage is 5-7 volts, go to step 2). If voltage is not 5-7 volts, go to step 3).
  2. Check For IDM Open  With ignition off, disconnect PCM. Disconnect ICM from ICM tee. Leave diagnostic cable connected to wiring harness connector. Connect a second breakout box to PCM harness connector. Set DVOM on ohm scale. Measure resistance between J41 (IDM I) at breakout box and pin No. 4 at PCM breakout box. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or greater, repair open in IDM circuit.
  3. Check IDM Output From ICM  With ignition off, set DVOM on AC voltage scale. Push and hold down IDM button at diagnostic cable connector (this opens IDM circuit to PCM). Start engine and measure voltage between J30 (diagnostic cable IDM DETECTOR) and J7 (B-) at breakout box. If AC voltage is greater than 5 volts, go to step 4). If voltage is 5 volts or less, replace ICM (no IDM output from module).
  4. Check For IDM Short In PCM (PCM Disconnected)  With ignition off, disconnect PCM. Crank engine and measure voltage between J30 (diagnostic cable IDM DETECTOR) and J7 (B-) at breakout box. If AC voltage is greater than 5 volts, replace PCM. If voltage is 5 volts or less, go to step 5).
  5. Check For IDM Short To Power In Harness  Turn ignition off. Ensure ICM and PCM are disconnected. Set DVOM on DC voltage scale. Turn ignition on. Measure voltage between J41 (IDM I) and J7 (B-) at breakout box. If voltage is less than 0.5 volt, go to step 6). If voltage is 0.5 volt or greater, repair IDM circuit for a short to power.
  6. Check For IDM Short To Ground  Turn ignition off. Disconnect ICM from diagnostic cable module tee. Leave diagnostic cable connected to wiring harness connector. Set DVOM on 20-k/ohm scale. Measure resistance between J41 (IDM I) and J7 (B-) at breakout box. If resistance is greater than 10 ohms, IDM is shorted to another circuit in wiring harness between ICM and PCM. If resistance is 10 ohms or less, IDM is shorted to ground. Repair or replace as necessary.
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