2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1531

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1531

3. Connect a 15 A fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative

terminal of the battery to relay terminal 86. Measure for less than 2 Ohms between terminals 30 and 87 of the relay.

瀚慖f greater than the specified value, replace the KR75 powertrain relay.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay

Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power

Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))

* Control Module References (See: Testing and Inspection/Programming and Relearning) for engine control module replacement, setup, and

programming

P0686

DTC P0685, P0686, P0687, P0689, or P0690 (LAU)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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/System Description

The engine controls (EC) ignition relay, or powertrain 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 switch contact at all times. The engine control module (ECM) supplies

the ground path to the relay coil control circuit via an internal integrated circuit called an output driver. When the ECM commands the powertrain

relay ON, ignition voltage is supplied to several fuses in the underhood fuse block.

The ignition 1 voltage that is supplied to the ECM through the ETC fuse 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 1 voltage circuit to confirm that the powertrain relay

contacts have closed.

Conditions for Running the DTC

P0685, P0686, and P0687