Code 51, Switch Condition Signal

ECM receives signal from P/N start switch, A/C amplifier and the idle contacts of the TPS. The ECM uses these input signals to determine the condition of the circuits when diagnostic check connector terminals "TE1" and "E1" are jumpered. When these diagnostic connectors are jumpered with engine running and Code 51 is not set, one or more of the input signals is not received by the ECM and inspection of all 3 circuits is required.

1. This checks for a problem with ignition switch on.
2. This checks for idle switch signal at ECM.
3. This checks for faulty Blue wire from TPS to ECM, a faulty ECM, or a misadjusted or faulty TPS.
4. This checks if P/N start system is functioning normally.
5. This check for an open in Black/White wire from P/N switch or for a faulty ECM.
6. This checks if A/C system is functioning normally.

Fig 1: Code 51 Schematic (GSi), Switch Condition Signal

Fig 2: Code 51 Flow Chart (GSi), Switch Condition Signal