Dtc P1664 (Flash Code 76) - Isuzu 2008MY N Series Workshop Manual

DTC P1664 (Flash Code 76)

Circuit Description
The service vehicle soon (SVS) lamp is located on the
instrument panel (IP) cluster. The SVS lamp informs
the driver that a non-emission related fault has
occurred and vehicle service required.
The ECM monitors the SVS lamp control circuit for
conditions that are incorrect for the commanded state
of the SVS lamp. For example, a failure condition exists
if the ECM detects low voltage when the SVS lamp is
commanded OFF, or high voltage when the SVS lamp
is commanded ON. If the ECM detects an improper
voltage level on the control circuit, this DTC will set.
Condition for Running the DTC
• 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 a low voltage condition on the
SVS lamp control circuit when the lamp is
commanded OFF.
Circuit/ System Testing DTC P1664
Step
Did you perform the Diagnostic System Check
1
- Engine Controls?
1. Verify whether the instrument panel (IP)
cluster is operational.
2. Install a scan tool.
3. Turn OFF the ignition for 30 seconds.
2
4. Turn ON the ignition for 10 seconds.
5. Start the engine.
6. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition?
1. Turn OFF the ignition.
2. Inspect the Meter (10A) fuse in the cab.
3
Is the Meter (10A) fuse open?
Replace the Meter (10A) fuse. If the fuse continues
to open, repair the short to ground on one of the
circuits that is fed by the Meter (10A) fuse or
4
replace the shorted attached component.
Did you complete the repair?
1. Turn OFF the ignition.
2. Disconnect the ECM J-14 harness connector.
5
3. Turn ON the ignition, with the engine OFF.
Is the SVS lamp OFF?
Action
Engine Control System (4HK1)
• The ECM detects a high voltage condition on the
SVS lamp control circuit when the lamp is
commanded ON.
Action Taken When the DTC Sets
• The ECM will illuminate the SVS lamp. Refer to
DTC Type Definitions for Action Taken when the
DTC Sets - Type C.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the SVS Lamp/ DTC - Type C.
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
Value(s) Yes
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Go to Step 2
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Go to Step 3
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Go to Step 4
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Go to Step 17
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Go toStep 6
1A-251
No
Go to Diagnostic
System Check -
Engine Controls
Go to Diagnostic
Aids
Go to Step 5
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Go to Step 12