DTC P0685, P0689, or P0690 - LDE or LLU
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 under bonnet 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.
- Ignition OFF, allow the ECM to completely power down.
Probe both test points of F1UA, F2UA, F3UA, F4UA and F8UA fuses
supplied with voltage by the KR75 Powertrain Relay. The test
lamp should not illuminate on any test point of any fuse.
- Ignition ON, probe both test points of F1UA, F2UA,
F3UA, F4UA and F8UA fuses supplied with voltage by the
KR75 Powertrain Relay. The test lamp should illuminate on at
lease one test point of each fuse.
- 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
- Ignition OFF, disconnect the KR75 Powertrain
Relay.
- Ignition ON, verify that a test lamp illuminates
between the KR75 Powertrain Relay coil B+ socket circuit
terminal 86 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. |
- Ignition OFF, connect a test lamp between the
KR75 Powertrain Relay coil control socket circuit
terminal 85 and the relay coil B+ socket circuit
terminal 86.
⇒ |
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. |
- 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.
- 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.
- Attempt to start the engine. The engine should
start.
- 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 terminal 3 for a short to ground or for an
open/high resistance. If the circuit tests normal, replace the
K20 Engine Control Module.
- If all circuits test normal, test or replace the
KR75 Powertrain Relay.
Component Testing
Relay Test
- Ignition OFF, disconnect the KR75 Powertrain
Relay.
- 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. |
- Measure for infinite resistance between following
terminals of the KR75 Powertrain Relay:
⇒ |
If continuity is detected, replace the
KR75 Powertrain Relay. |
- 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.
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