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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 847

6E–412

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1171 – Fuel System Lean During Acceleration

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Are any component-related DTCs set?

—

Go to

component

DTC charts

Go to

Step 3

1. Check the vehicle’s fuel tank for an adequate

amount of fuel.

2. Add fuel to the vehicle’s fuel tank if the tank is almost

empty.

Was fuel added to the vehicle’s fuel tank?

—

Go to

Step 4

Go to

Step 5

1. Place the transmission in park.
2. Using a Tech 2, observe HO2S 1 voltage while

running warm engine 75

C-95

C (167

F-203

F) at

1200 RPM.

3. HO2S 1 voltage should vary within the specified

range.

4. Quickly open the throttle too halfway for a few

seconds.

Did the voltage suddenly rise toward the high end of the
specified range?

100-900 mV

Go to

Fuel

System

Electrical Test

Go to

Step 5

1. Disconnect the fuel pump relay and crank the

engine to relieve the fuel pressure.

2. Install the fuel pressure gauge.
3. Start the engine and idle at normal operating

temperature.

4. Disconnect the vacuum line going to the fuel

pressure regulator.

With the engine running, is the fuel pressure within the
specified range?

280-325 kPa

(41-46 psi)

Go to

OBD

System

Check

Go to

Step 6

Check for restricted fuel lines or restricted in-line filter.

Was a problem found?

—

Verify repair

Go to

Step 7

1. Ignition “OFF”.
2. Remove the fuel pump relay and replace it with a

fused jumper which will connect the relay’s battery
terminal to the terminal leading to the fuel pump
fuse.

3. While the fuel pump is operating, use pliers to slowly

close the return line (do not exceed the first
specified value).

Using the pliers to restrict the return line, can the fuel
pressure be manipulated to exceed the second
specified value?

325 kPa

(46 psi)

414 kPa

(60 psi)

Check the

Procedure

Refer to

Diagnostic

Aids

Go to

Step 8

Check for:

Faulty fuel pump

Restricted fuel pump strainer (sock)

Incorrect fuel pump

Incorrect fuel being used

Hot fuel

Is the action complete?

—

Verify repair

—

6E–413

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1220 Throttle Position Senser2 (TPS2) Circuit Fault

D06RY00088

Circuit Description

The throttle position (TP2) sensor circuit provides a
voltage signal relative to throttle blade angle.
The throttle blade angle will vary about 8 % at closed
throttle to about 92 % at wide open throttle (WOT).

This code detects a continuous short to ground or
high in either the cicuit or the sensor.

Conditions for setting the DTC

The Ignition is “ON”.

The throttle blade angle is less than 2.5 % or more tnan
97.5 % for 18 failres within 500 test samples (15.6m
sec).

Action Taken When the DTC Sets

The PCM will store condition which were present when
the DTC was set as Freeze Frame and in the Failure
Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condtion is no longer present.

A history DTC P1120 will clear after 40 consecutive trip
cycle during which the warm up cycles have occurred
without a fault.

DTC P1120 can be cleared using the Tech2 “Clear Info”
function or by disconnecting the PCM battery feed.

Diagnostic Aids

An intermittent may be caused by the following:

Poor connectons.

Mis routed harness.

Rubbed through wire insulation.

Broken wire inside the insulation.

Check for the following conditions:

The CKP sensor shares 5 Volt reference with the TP
sensor 2. If these codes are also set, it could indicate
a problem with the 5 Volt reference curcuit.

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
TP sensor 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 DTC P1120 cannot be duplicated,the
information included in the Faillure Records data can
be useful in determined vehicle mileage since the
DTC was last set.

If it is determined that the DTC occurs
intermittently,performing the DTC

P1120 Diagnostic Chart may isolate the cause of the fault.

6E–414

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1220-TPS 2 Circuit Fault

Step

Action

Value(s)

Yes

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

—

Go to

Step 2

Go to

OBD

System

Check

Was the “Electric Throttle Control (ETC) System
Check” performed?

—

Go to

Step 3

Go to

ETC

System

Check

1. Disconnect the CKP sensor.
2. Connect a test 5 volt reference circuit and the CKP

signal at the CKP sensor harness connector.

3. Observe the CKP reading on the DVM.

Is the CKP reading less than the specified value? (If no,
start with diagnosis chart for other sensors in the circuit
and see if 5V returns.)

Go to

Step 5

Go to

Step 4

1. Check the CKP signal circuit between the PCM and

CKP ground circuit.

2. If the CKP signal circuit is open or shorted, repair as

necessary.

Was the CKP signal circuit open or shorted?

—

Verify repair

Go to

Step 16

Replace the CKP sensor.

Is the action complete?

—

Verify repair

—

1. Ignition “ON”, engine not running.
2. Observe the AP2 reading on the Tech2.

Is the AP2 reading less than the specified value?

Closed

throttle APS2

= 85

∼

89%

Wide open

throttle APS2

= 11

∼

15%

Go to

Step 7

Go to

Step 10

1. Disconnect the AP sensor 2.
2. Connect the Tech2 5 Volt reference circuit and the

AP2 signal at the Ap2 sensor harness connector.

3. Observe the AP2 reading on the Tech 2.

Is the AP2 reading less than the specified value? (If no,
start with diagnosis chart forother sensors in the circuit
and see if 5V returns.)

—

Go to

Step 9

Go to

Step 8

1. Check the Ap2 sensor signal circuit between the

PCM and AP2 sensor grund circuit.

2. If the AP2 sensor signal circuit open or shoted,

repair it as necessary.

Was the AP2 sensor signal circuit open or shorted?

—

Verify repair

Go to

Step 16

Replace the AP sensor 2.

Is the action complete?

—

Verify repair

—

6E–415

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1220-TPS 2 Circuit Fault

(Cont'd)

Step

Yes

Value(s)

Action

1. Warming up the engine until the ECT rise at 80

2. Ignition “OFF”.
3. Ignition “ON” but not engine run.
4. Observe the TP angle reading on the Tech 2 while

alowly opening the throttle.

NOTE: The value check of TPS must be performed in
less than 15 seconds.

Does the TP angle increase steadily and evenly from
the closed throttle value to the wide open throttle
value?

Closed

throttle
TPS2=

∼

94% Wide

open throttle

TPS2=

∼

23%

Go to

Step 11

Go to

Step 12

Was the DTC P1220 stored?

—

Go to

Step 16

Check the

procedure.

Refer to

Diagnostic

Aids

1. Connect a DVM between the 5Volt reference circuit

and the TP2 sensor ground circuit at the TPsensor
harness connector.

2. Observe the voltage using a DVM.

Is the voltage near the specified value?

Go to

Step 13

Go to

Step 16

Check the following items;

1. TP2 signal circuit for a short to voltage.
2. TP2 sensor ground circuit for high resistance

between the PCM and the TP2 sensor.

3. TP2 sensor ground circuit for a poor connection.
4. If a problem is found,repair wiring harness as

necessary.

Was a problem found?

—

Verify repair

Go to

Step 14

Check the following items;

1. TP2 signal circuit or 5 volt reference circuit for a

poor connection.

2. TP2 signal circuit or 5 volt reference circuit for high

resistance between the PCM and the TP sensor.

3. If a problem is found, repair wiring harness as

necessary.

Was a problem found?

—

Verify repair

Go to

Step 15

Replace the TP sensor.

Was a problem corrected?

—

Verify repair

Go to

Step 16

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 replasement PCM.

Is the action complete?

—

Verify repair

—

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