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 provide an overview of each diagnostic category.

### DTC Descriptor

DTC P0689: Engine Controls Ignition Relay Feedback Circuit Low Voltage

### Circuit/System 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.

### Conditions for Running the DTC

• | The battery voltage is more than 5 volts.

• | The ignition is ON.

• | The main relay has been commanded ON.

• | The DTC runs continuously once the above conditions are met.

### Conditions for Setting the DTC

• | The commanded state of the ODM and the actual state of the control circuit do not match.

| OR

• | The ECM detects that main relay feedback voltage is not within a predicted range, when the main relay is commanded ON or OFF.

• | Either condition is present for more than 2 seconds.

### Action Taken When the DTC Sets

DTC P0689 is a Type B DTC.

### Conditions for Clearing the MIL/DTC

DTC P0689 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Controls Connector End Views

• | Engine Control Module 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Ignition ON, observe the scan tool DTC Information parameter. DTC P0689 should not set.
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.

### Circuit/System Testing

1. Ignition OFF, disconnect the EC ignition or main relay.
2. Ignition ON, verify a test lamp illuminates between the coil voltage supply circuit and ground.

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

3. Ignition OFF, connect a test lamp between the control circuit and the coil voltage supply circuit.
4. Ignition ON, the test lamp should turn ON when the ignition switch is cycled ON and turn OFF when the ignition switch is cycled OFF.

⇒ | 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 ECM.

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

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

5. Connect a 15A fused jumper wire between the B+ supply voltage circuit and the ignition 1 voltage circuit.
6. Attempt to start the engine. The engine should start.

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

7. If all circuits test normal, test or replace the main relay.

### Component Testing

1. Test for 70-110 ohms of resistance between terminals 85 and 86.

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

2. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

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

3. 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 of resistance between terminals 30 and 87 of the relay.

⇒ | If greater than the specified range, replace the 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