Circuit Description
The Engine Controls 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. If the ECM detects a short to voltage on the control circuit of the relay, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1610 Engine Controls Ignition Relay Control Circuit High Voltage
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | DTC P1610 runs continuously once the above condition is met. |
Conditions for Setting the DTC
The ECM detects a short to voltage on the control circuit of the relay.
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | Using the scan tool can clear DTCs. |
| • | Disconnect the ECM battery feed for 10 seconds. |
Diagnostic Aids
| • | For an intermittent condition, refer to Intermittent Conditions . |
| • | The following table illustrates the Main Relay terminal location in the underhood fuse block: |
ENGINE Relay Terminal Identification | |
|---|---|
Control | |
B+ - Coil | Feedback |
B+ - Switch | |
Front of Vehicle | |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |
2 |
Do you hear an audible click from the relay? | Go to Step 3 | Go to Step 4 |
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 7 |
5 | Test the control circuit of the ENGINE relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
6 | Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the ENGINE relay. Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 |
10 | Are there any DTCs that have not been diagnosed? | System OK | |
