For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P1610: Engine Controls Ignition Relay Control Circuit High Voltage
DTC P1611: Engine Controls Ignition Relay Control Circuit Low Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage - Coil | P0562, P1611 | P0562, P1611 | -- | --
B+ Voltage - Switch | P0562, P1611 | P0562, P1611 | -- | --
EC Ignition Relay Control | P0563, P1611 | P0562, P1611 | P0562, P1610 | --
EC Ignition Relay Feedback | P0562, P1611 | P0562, P1611 | -- | --

### Circuit/System Description

The engine controls (EC) ignition relay or ENGINE 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.

### Conditions for Running the DTC

• | The ignition is ON or the engine is operating.

• | The DTCs run continuously once the above condition is met.

### Conditions for Setting the DTC

#### P1610

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

#### P1611

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

### Action Taken When the DTC Sets

DTC P1610 and P1611 are Type A DTCs.

### Conditions for Clearing the DTC

DTC P1610 and P1611 are Type A DTCs.

### Diagnostic Aids

The following table illustrates the ENGINE relay terminal location in the underhood fuse block:

ENGINE Relay Terminal Identification
Feedback | B+ - Coil
Control | B+ - Switch
Front of Vehicle

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, command the EC ignition relay ON with a scan tool. You should hear an audible click for about 3-5 seconds.
2. 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.

### Circuit/System Testing

1. Ignition OFF, disconnect the EC ignition relay.
2. Ignition ON, command the fuel pump relay ON with a scan tool. Test for battery voltage between the relay switch ignition 1 voltage circuit terminal 86 and ground.

⇒ | If less than B+, repair the relay switch ignition 1 voltage circuit for a short to ground or an open/high resistance.

3. Test for less than 0.1 volts between the relay coil B+ voltage circuit terminal 30 and 12 volts.

⇒ | If greater than the specified range, repair the relay coil B+ voltage circuit for a short to ground or an open/high resistance.

4. Ignition OFF, connect a test lamp between the relay switch control circuit terminal 85 and the relay switch ignition 1 voltage circuit terminal 86.
5. Ignition ON, command the EC ignition relay ON with a scan tool. The test lamp should turn ON for about 3-5 seconds and then turn OFF.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.

Important: The ignition 1 voltage circuit is between the EC ignition relay and the ECM. The ignition 1 voltage is a feedback circuit.

6. Connect a 15A fused jumper wire between the relay coil B+ supply voltage circuit terminal 30 and the relay switch ignition 1 voltage circuit terminal 86.
7. Attempt to start the engine. The engine should start.

⇒ | If the engine does not start, test the relay switch ignition 1 voltage circuit between the EC ignition relay and the ECM for a short to ground or for an open/high resistance. If the circuit tests normal, replace the ECM.

8. If all circuits test normal, test or replace the EC ignition relay.

### Component Testing

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

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

4. Install a 20A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

⇒ | If greater than the specified range, replace the EC ignition relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

• | Control Module References for engine control module replacement, setup, and programming