The powertrain relay is controlled by the engine control module (ECM) depending upon input from the ignition switch. Battery positive voltage is supplied to the relay coil and switch. When the ignition switch is turned to the ON position, the ECM will provide ground on the control circuit of the relay using a low side driver. This will allow voltage through the relay switch contacts to the components. The ECM monitors the voltage level on the control circuit of the relay.

P068A

P068B

The ECM detects the powertrain relay control circuit is open, shorted to ground, or shorted to voltage.

DTCs P068A or P068B are Type C DTCs.

DTCs P068A or P068B are Type C DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Note: If you were sent here from Engine Cranks But Does Not Run proceed to Circuit/System Testing.

1. Ignition ON, observe the DTC information with a scan tool. DTCs P068A or P068B should not set.
2. Cycle the ignition from OFF to ON. You should hear and feel an audible click from the KR75 Powertrain Relay. Repeat as necessary in order to verify KR75 Powertrain Relay operation.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the KR75 Powertrain Relay.
2. Ignition ON, verify that a test lamp illuminates between the relay coil ignition voltage circuit terminal 85 and ground.

⇒	If the test lamp does not illuminate, repair the relay coil ignition voltage circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect a test lamp between the relay coil control circuit terminal 86 and the relay coil ignition voltage circuit terminal 85. The test lamp should not be illuminated.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

4. Ignition ON. The test lamp should turn ON.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

5. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
6. Attempt to start the engine. The engine should start.

⇒	If the engine does not start, test the ignition circuit between the KR75 Powertrain Relay and the K20 Engine Control Module (ECM) for a short to ground or for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

7. If all circuits test normal, test or replace the KR75 Powertrain Relay.

1. Ignition OFF, disconnect the main ignition relay.
2. Test for 70-110 Ω between terminals 85 and 86.

⇒	If not within the specified range, replace the KR75 Powertrain Relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the KR75 Powertrain Relay.

4. Install a 10 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the KR75 Powertrain Relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.