*CHECKING THE ECM POWER AND GROUND CIRCUITS







Possible Causes
(K51) ASD RELAY CONTROL CIRCUIT OPEN
(F344) ASD RELAY OUTPUT CIRCUIT(S) OPEN
CHECKING THE ASD RELAY SYSTEM
(Z905) ECM GROUND CIRCUIT(S) OPEN
FUSED ASD RELAY BATTERY SUPPLY CIRCUIT OPEN
(F202) FUSED IGNITION SWITCH (START/RUN) OUTPUT CIRCUIT OPEN
SUBSTITUTE ASD RELAY
(K51) ASD RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE



Diagnostic Test

1. ECM GROUND CIRCUIT(S) OPEN



Turn the ignition off.
Disconnect the ECM harness connectors.
Using a 12-volt test light connected to 12-volts, check each of the ECM ground circuits in ECM harness connector C2 cavities 2, 4 and 6.

Did the test light illuminate for each cavity?

Yes


No

2. (F202) FUSED IGNITION SWITCH START/RUN OUTPUT CIRCUIT OPEN



Turn the ignition to the Start position.
Using a 12-volt test light connected to ground, check the (F202) Fused Ignition Switch Start/Run Output circuit in ECM harness connector C2 cavity 41.
Turn the ignition to the Run position.
Using a 12-volt test light connected to ground, check the (F202) Fused Ignition Switch Start/Run Output circuit in ECM harness connector C2 cavity 41.

Is the test light on for both ignition switch positions?

Yes


No

3. CHECKING THE ASD RELAY SYSTEM



Turn the ignition off.
Connect a jumper wire between ground and the (K51) ASD Relay Control circuit in ECM C2 harness connector cavity 42.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the (F344) Fused ASD Relay Output circuits at the ECM C2 harness connector cavities 1, 3 and 5.

Does the test light illuminate brightly for each circuit?

Yes


No

4. FUSED ASD RELAY BATTERY SUPPLY CIRCUIT OPEN



Turn the ignition off.
Remove the ASD Relay from the TIPM.
Using a 12-volt test light connected to ground, check both Fused ASD Relay Battery Supply circuits in ASD Relay connector.

Is the test light on?

Yes


No

5. (F344) ASD RELAY OUTPUT CIRCUIT OPEN



Connect a jumper wire between cavity 30 and cavity 87 in the ASD Relay connector.
Using a 12-volt test light connected to ground, check the (F344) ASD Relay Output circuit in ECM harness connector C2 cavities 1, 3 and 5.

Did the test light illuminate for each circuit?

Yes


No

6. ASD RELAY



Turn the ignition off.
Install a known good relay in place of the ASD Relay.
Connect a jumper wire between ground and the (K51) ASD Relay Control circuit in ECM C2 harness connector cavity 42.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the (F344) Fused ASD Relay Output circuits at the ECM C2 harness connector cavities 1, 3 and 5.

Did the test light illuminate brightly for each circuit?

Yes


No

7. (K51) ASD RELAY CONTROL CIRCUIT OPEN



Turn the ignition off.
Remove the ASD Relay from the TIPM.
Measure the resistance of the (K51) ASD Relay Control circuit between the TIPM connector and the ECM harness connector.

Is the resistance below 10.0 ohms?

Yes


No

8. (K51) ASD RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE



Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay connector in the TIPM.
Turn the ignition on.
Measure the voltage on the (K51) ASD Relay Control circuit.

Is the voltage above 1.0 volt?

Yes


No