ML1 - Malfunction Indicator Light Always On

NOTE: If vehicle will not start, perform Pinpoint Test

- AA1, if equipped with Distributor Ignition (DI) (49 States). AA1 - Identify Type of No Start

- AC1, if equipped with High Data Rate Electronic Ignition (California). AC1 - Attempt to Crank Engine

- If any Key On Engine Off Diagnostic Trouble Codes or Continuous Memory Diagnostic Trouble Codes are present, service before proceeding. If pass codes are present, continue with this test step.

- Key "OFF".

- Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.

- Install Breakout Box, leave PCM disconnected.

- Measure resistance between test pin 17 and test pin 40 at the Breakout Box.

- Is resistance less than 5.0 ohms?

Yes -- Service short circuit between test pin 17 and Malfunction Indicator Lamp (MIL), or between test pin 17 and the Data Link Connector. Remove breakout box. Reconnect PCM. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Replace PCM. Remove breakout box. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)