1A-220 Engine Control System (4HK1)
DTC P0641 (Flash Code 55)
Circuit Description
The ECM provides 5 volts reference voltage through
the reference circuit 1 to the following sensors:
• Accelerator pedal position (APP) sensor 1
• PTO throttle sensor
• Idle up sensor
The 5 volts reference circuits are bussed together
outside the ECM. Therefore, a short circuit condition on
one sensor 5 volts reference circuit may affect the
entire 5 volts reference circuit 1.The ECM monitors the
voltage on the 5 volts reference circuit 1. If the ECM
detects the voltage is excessively low or high, this DTC
will set.
Condition for Running the DTC
• DTC P060B is not set.
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
Condition for Setting the DTC
Either of following condition is met:
• The ECM detects that the 5 volts reference circuit
1 voltage is less than 4.5 volts.
• The ECM detects that the 5 volts reference circuit
1 voltage is more than 5.5 volts.
Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic
runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM blinks the exhaust brake indicator lamp
when the diagnostic runs and fails.
• The ECM limits fuel injection quantity.
• The ECM inhibits exhaust brake control.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the MIL/ DTC - Type A.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0641
Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check
- Engine Controls?
—
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
2
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition?
—
Go to Step 3
Go to Diagnostic
Aids
3
1. Turn OFF the ignition.
2. Disconnect the idle up sensor harness
connector.
3. Connect a DMM between the 5 volts reference
circuit (pin 3 of B-87) and a known good
ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage less than the specified
value?
5.5 volts
Go to Step 4 Go to Step 8
4
Is the DMM voltage more than the specified
value at Step 3?
4.5 volts
Go to Step 9 Go to Step 5
LG4HKED-WE-0871.book 220 ページ ２００７年１１月２９日 木曜日 午後６時２９分
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