Isuzu 2000 Trooper Workshop Manual page 1354

Diagnostic Trouble Code (DTC) P1635 Reference Voltage # 1 Circuit Fault
Step
1 Was the "On-Board(OBD)System Check" performed?
2 1. Ignition "ON", engine not running.
2. Using a DVM at the PCM side of the connector,
check the votage at terminal S38 (RED/BLU) pin.
Is the voltage in specified range?
3 1. Ignition "ON", engine not running.
2. Using a DVM at the PCM side of the connector,
check the votage at terminal F20 (WHT) pin.
Is the voltage in specified range?
4 1. Ignition "ON", engine not running.
2. Using a DVM at the PCM side of the connector,
check the votage at terminal F57 (WHT) pin.
Is the voltage in specified range?
5 Observe the battery voltage and circuit. If the probrem
found, repair it as necessary.
Was the probrem found?
6 Replace the PCM.
IMPORTANT:
The replacement PCM must be programmed. Refer to
ON-Vehicle Service in Power Control Module and
Sensors for procedures.
And also refer to latest Service Bulletin. Check to see if
the latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Action Value(s) Yes
— Go to Step 2
Go to ETC
System
4.95 – 5.0V Check
11.6 – 12.7V Go to Step 4
11.6 – 12.7V Go to Step 6
— Verify repair
— Verify repair
6E–485
No
Go to OBD
System
Check
Go to Step 3
Go to Step 5
Go to Step 5
Go to Step 6
—