DTC P068A or P068B
Diagnostic Instructions
DTC Descriptors
| DTC P068A 00: Engine Controls Ignition Relay
De-Energized Too Early |
| DTC P068B 00: Engine Controls Ignition Relay
De-Energized Too Late |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Relay Coil Ignition
|
P068A 00
|
P068A 00
|
—
|
—
|
Relay Switch Ignition
|
P068A 00
|
P068A 00
|
—
|
—
|
Relay Coil Control
|
P068B 00
|
—
|
—
|
—
|
Relay Output Control
|
—
|
—
|
P068B 00
|
—
|
|
| |
Circuit/System Description
The powertrain 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
P068A
| • |
The ignition is ON or the
engine is running. |
| • |
The DTCs run continuously once
the above condition is met. |
P068B
| • |
The ignition is switched
OFF. |
| • |
The DTC runs continuously
until the ECM powers down. |
Conditions for Setting the DTC
The ECM detects the powertrain relay control circuit is open,
shorted to ground, or shorted to voltage.
Action Taken When the DTC Sets
DTC P068A or P068B are Type C DTCs.
Conditions for Clearing the DTC
DTC P068A or P068B are Type C 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 ON, observe the DTC
information with a scan tool. DTCs P068A or P068B should not
set. |
| 2. |
Cycle the ignition from OFF to
ON. You should hear and feel an audible click from the KR75
Powertrain Relay. Repeat as necessary in order to verify KR75
Powertrain Relay operation. |
| 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 relay ignition voltage circuit
terminal 2 and earth. |
| ⇒ |
If the test lamp does not illuminate, repair the
relay coil igniting voltage circuit for a short to earth or an
open/high resistance. |
| 3. |
Ignition OFF, connect a test
lamp between the relay coil control circuit terminal 1 and the
relay coil ignition voltage circuit terminal 2. The test lamp
should not be illuminated. |
| ⇒ |
If the test lamp is always ON, test the 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 control
circuit for a short to voltage or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control Module. |
| 5. |
Connect a 20 A fused jumper
wire between the relay switch B+ circuit terminal 3 and the relay
switch ignition voltage circuit terminal 5. |
| 6. |
Attempt to start the engine.
The engine should start. |
| ⇒ |
If the engine does not start, test the ignition
circuit between the KR75 Powertrain Relay and the K20 Engine
Control Module for a short to ground or for an open/high
resistance. If the circuit tests normal, replace the K20 Engine
Control Module. |
| 7. |
If all circuits test normal,
test or replace the KR75 Powertrain Relay. |
Component Testing
Dynamic Test
| 1. |
Ignition OFF, disconnect the
main ignition relay. |
| 2. |
Test for 70–110 Ω
between terminals 85 and 86. |
| ⇒ |
If not within the specified range, replace the
KR75 Powertrain Relay. |
| 3. |
Test for infinite resistance
between the following terminals: |
| ⇒ |
If not the specified value, replace the KR75
Powertrain Relay. |
| 4. |
Install a 10 A fused jumper
wire between relay terminal 2 and 12 V. Install a jumper wire
between relay terminal 1 and ground. Test for less than 2 Ω
between terminals 3 and 5. |
| ⇒ |
If greater than the specified range, replace the
KR75 Powertrain Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
