Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 837

6E–372

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1107 MAP Circuit Intermittent Low Voltage

D06R200048

Circuit Description

The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure (vacuum). The
MAP sensor signal voltage to the powertrain control
module (PCM) varies from below 2 volts at idle (high
vacuum) to above 4 volts with the ignition “ON”, engine
not running or at wide-open throttle (low vacuum).
The MAP sensor is used to determine manifold pressure
changes while the linear EGR flow test diagnostic is being
run (refer to

DTC P0401), to determine engine vacuum

level for some other diagnostics and to determine
barometric pressure (BARO). The PCM compares the
MAP sensor signal to a calculated MAP based on throttle
position and various engine load factors. If the PCM
detects a MAP signal that is intermittently below the
calculated value, DTC P1107 will be set.

Conditions for Setting the DTC

No TP sensor DTCs are present.

Engine is running.

Ignition voltage is more than 11 volts.

Throttle angle is above 1% if engine speed is less than
1000 RPM.

Throttle angle is above 3% if engine speed is above
1000 RPM.

The MAP sensor indicates an intermittent manifold
absolute pressure below 11 kPa for a total of

approximately 5 seconds over a 16-second period of
time.

Action Taken When the DTC Sets

The PCM will not illuminate the malfunction indicator
lamp (MIL).

The PCM will store conditions which were present
when the DTC was set as Failure Records data only.
This information will not be stored as Freeze Frame
data.

Conditions for Clearing the MIL/DTC

A history DTC P1107 will Clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1107 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

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.

The MAP Sensor shares a 5 Volt reference with the
EGR Valve. If these codes are also set, it could indicate
a problem with the 5 Volt reference circuit or
components itself.

The MAP Sensor share a ground with the EGR Valve
and the IAT Sensor.

6E–373

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Damaged harness – Inspect the wiring harness for
damage. 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.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

DTC P1107 – MAP Sensor Circuit Intermittent Low Voltage

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

Is DTC P0108 also set?

—

Go to

DTC

P0108 chart

first

Go to

Step 3

Are DTC P1111, P1115, and/or P1120 also set?

—

Go to

Step 6

Go to

Step 4

Check for a poor sensor ground circuit terminal
connection at the MAP sensor.

Was a problem found?

—

Go to

Step 9

Go to

Step 5

Check the MAP signal circuit between the MAP sensor
connector and the PCM for an intermittent short to
voltage.

Was a problem found?

—

Go to

Step 10

Go to

Step 8

Check for an intermittent short to voltage on the 5 volt
reference circuit between the PCM and the following
components:

MAP sensor

EGR valve

TP sensor

Was a problem found?

—

Go to

Step 10

Go to

Step 7

Check for a poor sensor ground circuit terminal
connection at the PCM.

Was a problem found?

—

Go to

Step 9

Go to

Step 8

Check for an intermittent open or a faulty splice in the
sensor ground circuit.

Was a problem found?

—

Go to

Step 10

Check the

Procedure

Refer to

Diagnostic

Aids

Replace the faulty harness connector terminal for the
sensor ground circuit.

Is the action complete?

—

Verify repair

—

Locate and repair the intermittent open/short circuit in
the wiring harness as necessary.

Is the action complete?

—

Verify repair

—

6E–374

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1111 IAT Sensor Circuit Intermittent High Voltage

D06RY00168

Circuit Description

The intake air temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the
engine. The powertrain control module (PCM) applies 5
volts through a pull-up resistor to the IAT sensor. When
the intake air is cold, the sensor resistance is high and the
PCM will monitor a high signal voltage on the IAT signal
circuit. If the intake air is warm, the sensor resistance is
lower causing the PCM to monitor a lower voltage. DTC
P1111 will set when the PCM intermittently detects an
excessively high signal voltage on the intake air
temperature sensor signal circuit.

Conditions for Setting the DTC

The engine has been running for over 30 seconds.

Vehicle speed is less than 32 km/h (20 mph).

Engine coolant temperature is above 60

C (140

F).

Mass air flow is less than 20g/second.

IAT signal voltage indicates and intake air temperature
intermittently less than –39

C (–38

F) (about 5 volts)

for approximately 2.5 seconds over a 25-second
period of time.

Action Taken When the DTC Sets

The PCM will substitute a default value for intake air
temperature.

The PCM will store conditions which were present
when the DTC set as Failure Records data only. This
information will not be stored as Freeze Frame data.

DTC P1111 does not illuminate the MIL.

Conditions for Clearing the MIL/DTC

A history DTC P1111 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P1111 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

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.

Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
IAT display on the Tech 2 while moving connectors and
wiring harnesses related to the IAT sensor. A change
in the IAT display will indicate the location of the fault.

6E–375

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Intake Air Temperature Sensor

OHMS

Temperature vs. Resistance Values

(approximate)

100

212

177

176

332

140

667

113

1188

1802

2796

4450

7280

–5

12300

–15

21450

–30

–22

52700

–40

100700

Content .. 835 836 837 838 ..