The engine controls (EC) ignition relay or main 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.

DTC P1610

The ECM detects a short to voltage on the control circuit of the relay.

DTC P1611

The ECM detects an open or short to ground on the control circuit of the relay.

DTC P1610 and P1611 are Type C DTCs.

DTC P1610 and P1611 are Type C DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Engine Controls Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. With the ignition ON, command the EC ignition relay ON with a scan tool. You should hear an audible click for 3-5 seconds.
2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

1. Ignition OFF, disconnect the EC ignition relay.
2. Ignition ON, verify that a test lamp illuminates between both B+ voltage circuit terminals 85/30 and ground.

⇒	If the test lamp does not illuminate, repair the B+ voltage circuit for a short to ground or an open/high resistance. Replace the fuse as necessary

3. Ignition OFF, connect a test lamp between the control circuit terminal 86 and the B+ voltage circuit terminal 85.
4. Install a 3-amp fused jumper wire between the control circuit terminal 87 and the B+ voltage circuit terminal 30.
5. Ignition ON, use a scan tool to command the EC ignition relay ON. The test lamp should turn ON and OFF for 3-5 seconds.

⇒	If the test lamp remains ON all the time, test for a short to ground on the control circuit. If the circuit/connections test normal, replace the ECM.

⇒	If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.

6. If all circuits/connections test normal, test or replace the EC ignition relay.

1. Measure for 70-110 ohms of resistance between terminals 85 and 86 of the EC ignition relay.

⇒	If the resistance is not within the specified range, replace the EC ignition relay.

2. Measure for infinite resistance between the following terminals of the EC ignition relay:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If continuity is detected, replace the EC ignition relay.

3. Connect a 20-amp fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.

⇒	If the resistance measures more than 2 ohms, replace the EC ignition relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.