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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 349

6E–426

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)

Go 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–427

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P1220 Throttle Position Senser2 (TPS2) Circuit Fault

D06RY00111

Circuit Description

The throttle position (TP2) sensor circuit provides a
voltage signal relative to throttle blade angle.
The TPS2 voltage will vary from about 8% (0.4V) to
about 92% (4.6V) at Wide Open Throttle (WOT) in
the specified voltage (about 5V).

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

Conditions for setting the DTC

The Ignition is “ON”.

The TPS2 output is more than 93.6 milliseconds, less
than 2.5% or more than 97.5% in the specified voltage
(5V).

Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected fault.

The PCM will store conditions 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 condition is no longer present.

A history DTC P1120 will clear after 40 consecutive trip
cycles 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 connections.

Misrouted harness.

Rubbed through wire insulation.

Broken wire inside the insulation.

Check for the following conditions:

The MAP sensor shares a 5 Volt reference with the
Fuel Tank Pressure. If these codes are also set, it could
indicate a problem with the 5 Volt reference circuit.

The MAP sensor shares a ground with the Fuel Tank
Pressure, the ECT sensor, and the Transmission Fluid

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

6E–428

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

information included in the Failure 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.

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. Ignition “ON”, engine not running.
2. Observe the MAP reading on the Tech 2.

Is the MAP reading less than the specified value?

65 kPa

Go to

Step 4

Go to

Step 7

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

signal at the MAP sensor harness connector.

3. Observe the MAP reading on the Tech 2.

Is the MAP 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 6

Go to

Step 5

1. Check the MAP signal circuit between the PCM and

MAP ground circuit.

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

necessary.

Was the MAP signal circuit open or shorted?

—

Verify repair

Go to

Step 13

Replace the MAP sensor.

Is the action complete?

—

Verify repair

—

Observe the TP angle reading on the Tech-2 while
slowly opening the throttle.

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

Closed TPS1

8–10 % TPS2

8–10 % WTO

TPS1 90–92

% TPS2

90–92 %

Refer to

Diagnostic

Aids

Go to

Step 8

1. Disconnect the TP sensor.
2. Observe the TP sensor reading on the Tech2.

Is the TP sensor reading near the specified value?

Go to

Step 9

Go to

Step 10

1. Connect a test light between the 5Volt reference

circuit and the TP2 sensor signal circuit at the TP
sensor harness connector.

2. Observe the TP sensor reading on the Tech 2.

Is the TP sensor reading near the specified value?

Go to

Step 12

Go to

Step 11

6E–429

6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P1220-TPS 2 Circuit Fault

(Cont'd)

Step

Yes

Value(s)

Action

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 13

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 13

Replace the TP sensor.

Is the action complete?

—

Verify repair

—

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 replacement PCM.

Is the action complete?

—

Verify repair

—

Content .. 347 348 349 350 ..