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DTC P0685, P0686, P0687, P0689, or P0690

DTC P0685, P0686, P0687, P0689, or P0690

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 P0685

Engine Controls Ignition Relay Control Circuit

DTC P0686

Engine Controls Ignition Relay Control Circuit Low Voltage

DTC P0687

Engine Controls Ignition Relay Control Circuit High Voltage

DTC P0689

Engine Controls Ignition Relay Feedback Circuit Low Voltage

DTC P0690

Engine Controls Ignition Relay Feedback Circuit High Voltage

Diagnostic Fault Information

Circuit Short to Ground High Resistance Open Short to Voltage Signal Performance
Battery Supply Voltage - Coil

P0685

P0685

P0685

-

-

Battery Supply Voltage - Armature

-

P0689

P0689

P0690

-

Relay Control Circuit

P0686

P0685

P0685

P0687

P0685

Relay Feedback Circuit

-

P0689

P0689

P0690

-



Typical Scan Tool Data

EC Ignition Relay Feedback Signal

Circuit Normal Range Short to Ground Open Short to Voltage
Operating Conditions: Ignition ON, engine OFF.

Battery Supply Voltage - Coil

-

0 V

0 V

-

Battery Supply Voltage - Armature

-

0 V

0 V

-

EC Ignition Relay Control

-

0 V

0 V

-

EC Ignition Relay Feedback

11.9-12.9 V

0 V

0 V

More than 2 V¹

¹DTC P0690 will set if the ECM detects voltage when the ignition is in the OFF position.



Circuit/System Description

The powertrain/engine controls (EC) ignition relay is a normally open relay. The relay switch is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the relay switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit through an output driver module (ODM). The ODM for the relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the relay ON, ignition voltage is supplied to fuses in the underhood fuse block.

The ignition voltage that is supplied to the ECM provides power to the internal ECM circuits associated with the throttle actuator control (TAC) operation. The ECM also monitors the voltage level on the ignition voltage circuit to confirm that the powertrain relay contacts have closed.

Conditions for Running the DTC


P0685 and P0686

The battery voltage is between 10.5-18 V.

The ignition is ON.

The relay has been commanded ON.

These DTCs run continuously when the above conditions have been met.



P0687, P0689, and P0690

The battery voltage is between 10.5-18 V.

The ignition is OFF.

The powertrain relay has been commanded OFF.

These DTCs run continuously when the above conditions have been 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 the feedback voltage is not within a predicted range when the relay is commanded ON and OFF.

Either condition is present for more than 2 s.


Action Taken When the DTC Sets

DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.

Conditions for Clearing the DTC

DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.

Diagnostic Aids


This test procedure assumes that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test .

When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the mating electrical terminals for correct tension.


Reference Information

Schematic Reference


Engine Controls Schematics

Power Distribution 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

Probing Electrical Connectors

Electrical Center Identification Views


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools


EL 43244 Relay Puller Pliers

J 44603 Injector Test Lamp


For equivalent regional tools, refer to Special Tools .

Circuit/System Verification

Note
A short to voltage on other components may cause DTC P0690 to set. If other DTCs are set, diagnose those DTCs first.

If you were sent here from Engine Cranks But Does Not Run, proceed to Circuit/System Testing.



1. Ignition ON, command the Engine Controls Ignition Relay ON and OFF with a scan tool while observing the following Engine Controls Ignition Relay control circuit status parameters:

Engine Controls Ignition Relay Control Circuit Low Voltage Test Status

Engine Controls Ignition Relay Control Circuit Open Test Status

Engine Controls Ignition Relay Control Circuit High Voltage Test Status

Each parameter should toggle between OK and Not Run or Not Run and OK.

2. Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTC P0685, P0686, P0687, P0689 or P0690 are not set.

3. 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

Note

You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.



1. Ignition OFF, disconnect the KR75 powertrain relay.

2. Verify that a test lamp illuminates between both of the following relay battery voltage circuit terminals and ground:

Terminal 85

Terminal 30

3. If the test lamp does not illuminate, test the relay battery voltage circuit for an open/high resistance.

4.
Note

The ignition voltage circuit is between the engine control module relay and the ECM. The ignition voltage circuit is a feedback circuit.


Ignition ON, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground.

5. If the test lamp illuminates, test the ignition voltage circuit for a short to voltage.

6. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.

7. Ignition ON, observe the scan tool Engine Controls Ignition Relay Feedback Signal parameter. The ECM should communicate, and the parameter should display 9-14 V.

8. If not the specified range, or the ECM does not communicate, test the ignition voltage circuit between the engine control module relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.

9. Ignition OFF, connect a DMM set to the diode setting between control circuit terminal 86 and ground. Verify the DMM displays OL.

10. If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.

11. Ignition ON, verify the DMM displays less than 1 V.

12. If not the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

13. If all circuits test normal, replace the KR75 powertrain relay.


Component Testing


1. Measure for 70-110 Ω between terminals 1 and 2 of the KR75 Powertrain Relay.

2. If the resistance is not within the specified range, replace the KR75 Powertrain Relay.

3. Measure for infinite resistance between following terminals and the KR75 Powertrain Relay:

Terminals 5 and 2

Terminals 5 and 3

Terminals 5 and 1

Terminals 2 and 3

4. If continuity is detected, replace the KR75 Powertrain Relay.

5. Connect a 20 A fused jumper wire from the positive terminal of the battery to KR75 Powertrain Relay terminal 2. Connect a jumper wire from the negative terminal of the battery to KR75 Powertrain Relay terminal 1. Measure for less than 2 Ω between terminals 5 and 3 of the KR75 Powertrain Relay.

6. If the resistance measures more than 2 Ω, replace the KR75 Powertrain Relay.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)

Control Module References for ECM replacement, setup, and programming