Circuit Description
The engine controls ignition relay or ENG 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, DTC P1610 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 for 2.4 seconds.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Diagnostic Aids
| • | For an intermittent condition, refer to Intermittent Conditions . |
| • | The following table illustrates the ENG Main relay terminal location in the underhood fuse block: |
ENG Main Relay Terminal Identification | |
|---|---|
Feeback | Control |
B+ - Coil | B+ - Switch |
Front of Vehicle | |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Is the voltage less than the specified value? | 2 V | Go to Step 4 | Go to Step 3 |
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 7 |
5 | Test the control circuit of the ENG MAIN 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 ENG MAIN relay. Refer to Relay Replacement in Wiring Systems. 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 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
