Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 846

6E–408

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P1169 Fuel System Rich During Decel Fuel Cut Off (Bank 2)

D06R200010

Circuit Description

The powertrain control module(PCM)
continuously monitors the heated oxygen sensor (HO2S)
activity for 90 seconds after “closed loop” has been
enabled. During the monitoring period the powertrain
control module (PCM) counts the number of times a rich
to lean response is indicated and adds the amount of time
it look to complete all rich to lean transitions and lean to
rich transitions.
This code detects if Bank2 sensor indicated rich exhaust
while in Decel Fuel Cut Off (DFCO) for fuel control
sensors.

Conditions for setting the DTC

D

No related DTCs.

D

The engine coolant temperature is more than 60 

°

C

(140 

°

F).

D

Engine is operating in “closed loop” power enrichment
mode for 3 seconds.

D

While in “power enrichment” mode the oxygen sensor
voltage remains more than 600mV in DFCO.

Action Taken When the DTC Sets

D

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

D

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

Conditions for Clearing the MIL/DTC

D

A history DTC P1169 will clear after 40 consecutive trip
cycles during which the warm up cycles have occurred
without a fault.

D

DTC P1169 can be cleared using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

D

Check for faulty fuel injectors and fuel pump.

D

Check the pressure regulator.

6E–409

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P1169 Fuel System Rich During Decel Fuel Cut Off (Bank2)

 

Step

Action

Value(s)

Yes

No

1

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

—

Go to

 Step 2

Go to

 OBD

System

Check

2

Are any component related DTCs set?

Go to

component

DTC charts

Go to

 Step 3

3

1. Place the transmission in Park.
2. Using a Tech 2, HO2S 2 voltage while running warm

engine75 C – 95 C (167 F – 203 F) at 1200 RPM.

3. HO2S 1 voltages should vary within the specified

range. (100 – 900mV)

4. Quickly open the wide open the throttle for a few

seconds.

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

100 – 600 mV

Go to

 OBD

System

Check

Go to

 Step 4 

4

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 – 325Kpa

(41 – 46psi)

Go to

 OBD

System

Check

Go to

 Step 5

5

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 value?

Is the fuel pressure gauge reading near the specified
value?

325KPa

(46psi)

414KPa

(60psi)

Check the

Procedure

Refer to

Diagnostic

Aids

Go to

 Step 6

6

Check the following items;

D

Faulty fuel pump

D

Incorrect fuel pump

D

Incorrect fuel being used

D

Cold fuel. 

If a problem is found, repair one as necessary.

Was a problem found?

—

Verify repair

—

6E–410

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P1171 Fuel System Lean During Acceleration

D06R200010

Circuit Description

The powertrain control module (PCM) internal circuitry
can identify if the vehicle fuel system is capable of
supplying adequate amounts of fuel during heavy
acceleration (power enrichment).  The PCM monitors the
voltage of the oxygen sensor during power enrichment.
When a power enrichment mode of operation is
requested during “closed loop” operation (by heavy
acceleration), the PCM will provide more fuel to the
engine.  Under these conditions the PCM should detect a
“rich”  condition (high oxygen sensor voltage).  If this “rich”
exhaust is not detected at this time, a DTC P1171 will set.
A plugged fuel filter, restricted fuel line, restricted in-tank
filter or defective fuel pump can prevent adequate
amounts of fuel from being supplied during power
enrichment mode.

Conditions for Setting the DTC

D

No related DTCs.

D

Engine is operating in “closed loop power enrichment”
mode for 3 seconds.

D

Engine coolant temperature is above 60

°

C (140

°

F).

D

While in “power enrichment” mode the oxygen sensor
voltage remains below 400 mV for 3 seconds.

Action Taken When the DTC Sets

D

The PCM will not turn the malfunction indicator lamp
(MIL) “ON”.

D

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

Conditions for Clearing the MIL/DTC

D

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.

D

A history DTC P1171 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P1171 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

D

A restricted fuel filter or fuel line, restricted in-tank filter,
or a defective fuel pump may supply adequate
amounts of fuel at idle, but may not be able to supply
enough fuel during heavy acceleration.

D

Water or alcohol in the fuel may cause low HO2S
voltage during acceleration.

D

Check for faulty or plugged fuel injector(s).

D

Check for low fuel.

6E–411

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
4. When the engine is idling or at steady cruise, the

HO2S voltage should vary from between
approximately 100 mV to 900 mV.  It is possible to
measure a satisfactory fuel pressure at idle even
though the pressure may drop at high flow
requirements.  It may be necessary to watch fuel
pressure at high engine load.

5. Wrap a shop towel around the fuel pressure

connector to absorb any small amount of fuel
leakage that may occur when installing gauge.
Ignition “ON”, pump pressure should be 280-320
kPa.

7. Add Caution, Use correct pliers so damage to fuel

lines will not occur.