Isuzu 2000 Trooper Workshop Manual page 948

Multiple PCM Information Sensor DTCs Set
Step
1 Was the "On-Board (OBD) System Check" performed?
2 1. Turn the ignition "OFF," disconnect the PCM.
2. Turn the ignition "ON," check the 5 volt reference 1
and 2 circuit for the following conditions:
D
A poor connection at the PCM.
D
An open between the PCM connector and the
splice.
D
A short to ground.
D
A short to voltage.
Is there an open or short?
3 Repair the open or short.
Is the action complete?
4 Check the sensor ground circuit for the following
conditions:
D
A poor connection at the PCM or the affected
sensors.
D
An open between the PCM connector and the
affected sensors.
Is there an open or a poor connection?
5 Repair the open or the poor connection.
Is the action complete?
6 Following below the DTCs stored:
P1635, P1639, P1646
7 Measure the resistance below the items:
D
Between EGR sensor supply circuit and Vapor
Pressure Sensor supply circuit.
D
Between MAP sensor supply circuit and Vapor
Pressure Sensor supply circuit.
D
Between Vapor Pressure Sensor supply circuit
and PCM harness connector. (5Volt supply
circuit)
Does the resistance measure near the specified value?
8 Locate and repair the open circuit in the MAP or EGR or
Vapor Pressure sensor suppy circuit.
Is the action complete?
9 1. Disconnect the MAP , Vapor pressure sensor and
EGR connecter.
2. Ignition "ON."
3. Measure the resistance below the items:
D
MAP sensor GND circuit.
D
EGR GND circuit.
D
Vapor pressure sensor GND circuit.
Does the voltage resistance near the specified value?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Action Value(s) Yes
— Go to Step 2
Go to Step 3
—
— Verify repair
Go to Step 5
—
— Verify repair
Go to
applicable
— DTC table
— Go to Step 9
— Verify repair
— Go to Step 11
6E–79
No
Go to OBD
System
Check
Go to Step 4
—
Go to Step 6
—
Go to Step 7
Go to Step 8
—
Go to Step 10