TC1 - Enter Output State Diagnostic Test Mode

Diagnostic Trouble Codes (DTC) 91/621, 92/622, 93/626, 94, 629, 641 and 652 indicate solenoid did not change state when requested by the Powertrain Control Module (PCM).

DTC 566 or 629 indicates the CCS or SS3/4-4/3 circuits did not change state when requested by the PCM.

Possible causes:
- Damaged solenoid assembly.
- Open or shorted harness (internal/external).
- Damaged PCM.

NOTE: Do not use a STAR Tester for this step. Use a Analog Volt/Ohm Meter (VOM) or Digital Volt/Ohm Meter (DVOM).

- Disconnect electrical connector on the speed control servo, if equipped.

- VOM/DVOM on 20 volt scale.

- Connect negative test lead to Self Test Output (STO) circuit at Data Link Connector (DLC) and meter positive test lead to B+.

- Jumper STI circuit to SIG RTN at the DLC.

- Perform Key On Engine Off Self-Test until Continuous Memory DTC have been displayed. Quick Test Appendix (Detailed Testing Instructions)

- VOM/DVOM will indicate less than 1.0 volt when test is complete.

- Depress and release throttle.

- Does voltage increase?

Yes -- Remain in Output State test mode. Go to TC2. TC2 - Check Solenoid Electrical Operation

No -- Depress throttle to Wide Open Throttle (WOT) and release. If STO voltage does not go high, perform pinpoint test step QC1. Leave equipment hooked up. QC1 - Check For Codes 23, 53, 63, 121, 122 or 123