Isuzu 1999 RODEO Workshop Manual page 745

6E1–118 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
f Poor connection at PCM – Inspect harness connectors
for backed–out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal–to–wire connection.
f The MAP sensor shares a 5 Volt Reference with the TP
sensor and Fuel Pressure sensor.
If these codes are also set, it could indicate a
problem with the 5 Volt reference circuit.
f The MAP sensor share a ground with the TP sensor
and Fuel Pressure sensor.
Step
1 Was the "On–Board Diagnostic (OBD) System Check"
performed?
2 1. If the engine idle is rough, unstable or incorrect,
repair the idle problem before using this chart. Refer
to Symptoms section.
2. With the engine idling, note the MAP value on the
Tech 2.
Is the MAP reading above the specified value?
3 1. Ignition ON engine OFF
2. Review and record Tech 2 Failure Records data,
then clear the DTC's.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using the Tech 2, monitor "DTC" info for Diagnostic
Trouble Code P0108.
Does the Tech 2 indicate that DTC P0108 failed this
ignition?
4 1. Ignition OFF.
2. Disconnect the MAP sensor electrical connector.
3. Ignition ON.
4. Observe the MAP value displayed on the Tech 2.
Is the MAP value near the specified value? (if no, start
with the diagnosis chart for other sensors in the circuit
and see if 5V returns.)
5 Check the MAP sensor signal circuit; between the MAP
sensor and the Powertrain Control Module (PCM), for a
short to voltage.
Was the problem found?
6 Check the MAP sensor circuit, between the MAP
sensor and the PCM, the following conditions:
f
A short to ground
f
An open circuit
Was the problem found?
7 Check the 5 volt signal circuit, between the MAP
sensor and the PCM for the following conditions:
f
An open circuit
f
A short to ground
f
A short to voltage
Was the problem found?
DTC P0108 MAP Sensor Circuit High Input
Action
f Damaged harness – Inspect the wiring harness for
damage; an open circuit, a short to ground, or a short
to voltage. If the harness appears to be OK, observe
the MAP display on the Tech 2 while moving
connectors and wiring harnesses related to the sensor.
A change in the display will indicate the location of the
fault.
If Diagnostic Trouble Code P0108 cannot be duplicated,
the information included in the Failure Records data can
be useful in determining vehicle mileage since the
Diagnostic Trouble Code was last set.
Value(s)
— Go to Step 2
About 4V 90
kPa Go to Step 4
— Go to Step 4
0 V 10.3 kPa Go to Step 5
— Verify repair
— Verify repair
— Verify repair
Yes No
Go to OBD
System
Check
Go to Step 3
Refer to
Diagnostic
Aids
Go to Step 6
Go to Step 12
Go to Step 7
Go to Step 8