DTC P0685, P0689, or P0690 (LUJ)
Diagnostic Instructions
DTC Descriptors
DTC P0685 00: Engine Controls Ignition Relay
Control Circuit |
DTC P0689 00: Engine Controls Ignition Relay
Feedback Circuit Low Voltage |
DTC P0690 00: Engine Controls Ignition Relay
Feedback Circuit High Voltage |
Circuit/System Description
The powertrain relay is an electrical switch that opens and
closes under the control of the engine control module. The
powertrain 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. The output driver module
for the ignition main relay also incorporates a fault detection
circuit, which is continuously monitored by the ECM. When the ECM
commands the powertrain relay ON, switched battery voltage is
supplied to fuses in the underhood fuse block. The switched battery
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 switched
battery circuit to confirm that the powertrain relay contacts have
closed.
Conditions for Running the DTC
• |
The ignition is ON, or the
engine is running. |
• |
The ignition voltage is
between 11-18 V. |
• |
These DTCs run continuously
once the above conditions are met. |
Conditions for Setting the DTC
P0685 00
The ECM detects that the commanded state of the driver and the
actual state of the control circuit do not match for greater than 2
s.
P0689 00
The ECM detects the engine controls powertrain relay feedback
circuit is less than 5 V when the relay is commanded ON for 5 s.
P0690 00
• |
The ECM detects the engine
controls powertrain relay feedback circuit is greater than 2 V when
the relay is commanded OFF. |
• |
The ECM detects the engine
controls powertrain relay feedback circuit is greater than 18 V
when the relay is commanded ON. |
Action Taken When the DTC Sets
DTCs P0685 00, P0689 00, and P0690 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0685 00, P0689 00, and P0690 00 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Note: If you were sent here
from Engine Cranks But Does Not Run proceed to Circuit/System
Testing.
1. |
Ignition OFF, allow the ECM to
completely power down. Probe both test points of F9, F10, and F11
fuses supplied with voltage by the KR75 Powertrain Relay. The test
lamp should not illuminate on any test point of any fuse.
|
2. |
Ignition ON, probe both test
points of F9, F10, and F11 fuses supplied with voltage by the KR75
Powertrain Relay. The test lamp should illuminate on at lease one
test point of each fuse. |
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
1. |
Ignition OFF, disconnect the
KR75 Powertrain Relay. |
2. |
Ignition ON, verify that a
test lamp illuminates between the KR75 Powertrain Relay coil B+
socket circuit terminal 85 and ground. |
⇒ |
If the test lamp does not illuminate, repair the
KR75 Powertrain Relay coil B+ circuit for a short to ground or an
open/high resistance. |
3. |
Ignition OFF, connect a test
lamp between the KR75 Powertrain Relay coil control socket circuit
terminal 86 and the relay coil B+ socket circuit terminal
85. |
⇒ |
If the test lamp is always ON, test the KR75
Powertrain Relay coil control circuit for a short to ground. If the
circuit tests normal, replace the K20 Engine Control Module. |
4. |
Ignition ON. The test lamp
should turn ON. |
⇒ |
If the test lamp is always OFF, test the KR75
Powertrain Relay coil control circuit for a short to voltage or an
open/high resistance. If the circuit tests normal, replace the K20
Engine Control Module. |
|
Note: The ignition
voltage circuit is between the KR75 Powertrain Relay circuit 87 and
the ECM through fuse F10. The ignition voltage is a feedback
circuit.
|
5. |
Install a 15 A fused jumper
wire between the KR75 Powertrain Relay switch B+ socket circuit
terminal 30 and the KR75 Powertrain Relay switch ignition voltage
socket circuit terminal 87. |
6. |
Attempt to start the engine.
The engine should start. |
7. |
If the engine does not start,
test the KR75 Powertrain Relay switch ignition voltage circuit
between the KR75 Powertrain Relay circuit terminal 87 and the ECM
connector X2 terminals 3 and 5 for a short to ground or for an
open/high resistance. If the circuit tests normal, replace the K20
Engine Control Module. |
8. |
If all circuits test normal,
test or replace the KR75 Powertrain Relay. |
Component Testing
Relay Test
1. |
Ignition OFF, disconnect the
KR75 Powertrain Relay. |
2. |
Measure for 70-110 Ω
between terminals 85 and 86 of the KR75 Powertrain Relay.
|
⇒ |
If the resistance is not within the specified
range, replace the KR75 Powertrain Relay. |
3. |
Measure for infinite
resistance between following terminals of the KR75 Powertrain
Relay: |
⇒ |
If continuity is detected, replace the KR75 Powertrain
Relay. |
4. |
Connect a 20 A fused jumper
wire from the positive terminal of the battery to KR75 Powertrain
Relay terminal 85. Connect a jumper wire from the negative terminal
of the battery to KR75 Powertrain Relay terminal 86. Measure for
less than 5 Ω between KR75 Powertrain Relay terminal 30 and
KR75 Powertrain Relay socket terminal 87. |
⇒ |
If the resistance measures more than 5 Ω,
replace the KR75 Powertrain Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|