Isuzu 1999 RODEO Workshop Manual page 907

6E1–280 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DTC P0481 Cooling Fan 2 Control Circuit Malfunction
Step
1 Was the "On–Board Diagnostic (OBD) System Check"
performed?
2 1. Ignition ON, Engine OFF.
2. Review and record Tech 2 Failure Records data,
then clear the DTCs.
3. Operate the vehicle within the Failure Records
conditions as noted.
4. Using the Tech 2, monitor "DTC" info for DTC
P0480.
Does the Tech 2 indicate that DTC P0480 "Ran and
Passed?"
3 1. Ignition OFF.
2. Remove the Low Fan Relay from the Underhood
Electrical Center.
3. Ignition OFF.
4. Using a Digital Voltmeter (DVM), check for voltage
on the "ELEC. FAN" Fuse pin of the Low fan Relay
connector.
Does the DVM read the following value?
4 1. Ignition ON.
2. Using a DVM, check for voltage on the "ENGINE
FAN" Fuse pin of the Low Fan Relay connector.
Does the DVM read the following value?
5 Check the suspect circuit between the Low Fan Relay
connector and Fuse for the following conditions:
f
A short to ground
f
An open circuit
f
A short to voltage
Was the problem found?
6 1. Ignition OFF.
2. Disconnect the Powertrain Control Module (PCM)
connectors from the PCM.
3. Check the Low Fan Relay control circuit between
the PCM and Underhood Electrical Center for the
following conditions:
f
A short to ground
f
An open circuit
f
A short to voltage
Was the problem found?
7 1. Reinstall the High Fan Relay.
2. Using a fused jumper, ground the High Fan Relay
control circuit at the PCM connector.
3. Ignition ON, Engine OFF.
Does the fan run at High speed?
Action Value(s) Yes
— Go to Step 2
Refer to
Diagnostic
— Aids
12 Volts Go to Step 4
12 Volts Go to Step 6
— Verify repair
— Verify repair
— Go to Step 9
No
Go to OBD
System
Check
Go to Step 3
Go to Step 3
Go to Step 5
—
Go to Step 7
Go to Step 8