P1278

P1278-STARTER CONTROL CIRCUIT 2 HIGH (TIPM)

P1278 - Starter Control Circuit 2 High (TIPM):

WHEN MONITORED:
With the ignition on. Battery voltage greater than 10.4 volts and the ASD sense switch is on.

SET CONDITION:
Actual Starter state is not equal to desired state. One Trip Fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- (T40) Starter relay output circuit shorted to battery voltage
- (T750) Starter relay output circuit shorted to battery voltage
- Starter relay
- Starter
- TIPM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

DIAGNOSTIC TEST

1. ACTIVE DTC
Ignition on, engine not running.
With a scan tool, read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (T40) STARTER FEED CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the Starter Relay.
Disconnect the C9 TIPM harness connector.
Turn the ignition on.
Measure the voltage of the (T40) Starter Relay Output circuit in the C9 TIPM harness connector.

Q: Is the resistance below 100 ohms?

YES: Repair the short to voltage in the (T40) Starter Relay Output circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3

3. (T750) STARTER RELAY OUTPUT CIRCUIT SHORTED TO BATTERY VOLTAGE
Disconnect the Starter Solenoid connector.
Measure the voltage of the (T750) Starter Relay Output circuit in the Starter Relay harness connector.

Q: Is the resistance below 100 ohms?

YES: Repair the short to voltage in the (T750) Starter Relay Output circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4

4. STARTER
Reconnect the Starter Solenoid harness connector.
Using a 12-volt test light connected ground, probe the (T750) Stater Relay Output circuit in the Starter Relay harness connector.
Crank the engine.

Q: Does the test light illuminate?

YES: Replace the Starter Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 5

5. STARTER RELAY INTERNAL SHORT
Install a substitute relay in place of the Starter Relay.
Reconnect the C9 TIPM harness connector.
Crank the engine.
With a scan tool, read DTCs.

Q: Does the DTC reset?

YES: Replace the TIPM. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace the Starter Relay. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test