Opel Frontera UE. Manual - part 208

6E1–130

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0171 SYSTEM TOO LEAN (BANK 1)

D06RX119

Circuit Description

To provide the best possible combination of driveability,
fuel economy, and emission control, a ”Closed Loop”
air/fuel metering system is used. While in ”Closed Loop”,
the engine control module (ECM) monitors the Bank 1
HO2S 1 signal and adjusts fuel delivery based upon the
HO2S signal voltage. A change made to fuel delivery will
be indicated by the long and short term fuel trim values
which can be monitored with a Tech 2. Ideal fuel trim
values are around 0%; if the HO2S signal indicates a lean
condition the ECM will add fuel, resulting in fuel trim
values above 0%. If a rich condition is detected, the fuel
trim values will be below 0%, indicating that the ECM is
reducing the amount of fuel delivered. If an excessively
lean condition is detected on Bank 1, the ECM will set
Diagnostic Trouble Code P0171. DTC P0171 is a type B
code.
The ECM’s maximum authority to control long term fuel
trim allows a range between –14% and +20%. The ECM
monitors fuel trim under various engine speed/load fuel
trim cells before determining the status of the fuel trim
diagnostic.

Conditions for Setting the DTC

No Tech 2 test is being run.

None of the following: EGR Diagnostic Trouble Codes,
HO2S Diagnostic Trouble Codes, (response,
transition, open, low volts, no activity), TP sensor
Diagnostic Trouble Codes, MAP Diagnostic Trouble

Codes, IAT Diagnostic Trouble Codes, canister purge
Diagnostic Trouble Codes, EVAP Diagnostic Trouble
Codes, injector circuit Diagnostic Trouble Codes, or
misfire Diagnostic Trouble Codes.

Engine coolant temperature is between 65

C (149

and 104

C (219

F).

Intake air temperature is between –40

C (–40

F) and

120

C (248

F).

Manifold absolute pressure is between 23.75 kPa and
99 kPa.

Engine speed is between 400 and 6000 RPM.

Barometric pressure is greater than 72.3 kPa.

System voltage is greater than 9.5v.

Engine is operating in ”Closed Loop”.

The average of the short term fuel trim samples is
greater than 0.97 and the average of adaptive index
multiplier samples is greater than 1.21.

Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The ECM will store conditions which were present
when the Diagnostic Trouble Code was set as Freeze
Frame and in the Failure Records data.

6E1–131

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Conditions for Clearing the MIL/DTC

The ECM 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 Diagnostic Trouble Code P0171 will clear
after 40 consecutivewarm–up cycles have occurred
without a fault.

Diagnostic Trouble Code P0171 can be cleared by
using the Scan Tool’s ”Clear Info” function.

Diagnostic Aids

Check for the following conditions:

Poor connection at ECM – 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; shorts to ground, shorts to battery positive
and open circuits. If the harness appears to be OK,
observe the Bank 1 HO2S 1 display on the Tech 2 while
moving connectors and wiring harnesses related to the
engine harness. 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 Diagnostic Trouble Code to
be set occurs. This may assist in diagnosing the
condition.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2.Diagnostic Trouble Codes other than P0171 may

indicate a condition present which may cause a lean
condition. If this is the case, repairing the condition
which caused the other Diagnostic Trouble Code will
most likely correct the Diagnostic Trouble Code
P0171.

4.If the Diagnostic Trouble Code P0171 test passes

while the Failure Records conditions are being
duplicated, the lean condition is intermittent. Refer
to Diagnostic Aids or Symptoms for additional
information on diagnosing intermittent problems.

6E1–132

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0171 – System Too Lean (Bank 1)

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 DTCs set other than P0171?

—

Go to the

applicable

DTC charts

and repair the

other DTCs

before

proceeding

with this

chart.

Go to Step 3

1. Start the engine and operate the vehicle in ”Closed

Loop”.

2. Observe the ”BANK 1 L.T. FUEL TRIM” and display

on the Tech 2.

Are the displayed values greater than the specified
values?

L.T. Fuel

Trim: 20%

Go to Step 5

Go to Step 4

1. Review and record the Tech 2 Failure Records data.
2. Clear the Diagnostic Trouble Code P0171 and

operate the vehicle to duplicate the Failure Records
conditions.

3. Monitor the Tech 2 “Diagnostic Trouble Code” info

for Diagnostic Trouble Code P0171 while operating
the vehicle to duplicate the Failure Records
conditions.

4. Continue operating the vehicle until the Diagnostic

Trouble Code P0171 test runs and note the test
result.

Does the Tech 2 indicate Diagnostic Trouble Code
P0171 failed this ignition?

—

Go to Step 5

The lean

condition is

not present. If

a driveability

symptom still

exists, refer

to Symptoms

section.

Visually and physically inspect the vacuum hoses for
disconnects, splits, kinks, improper routing and
improper connections and repair any problem found.

Did your inspection reveal a problem requiring repair?

—

Verify repair

Go to Step 6

Visually and physically inspect the crankcase
ventilation valve for proper installation and repair any
problem found (refer to Crankcase Ventilation
System).

Did your inspection reveal a problem requiring repair?

—

Verify repair

Go to Step 7

Start the engine and note the idle quality.

Is a high or unsteady idle being experienced?

—

Go to Step 8

Go to Step

With the engine idling, observe the ”IDLE AIR
CONTROL” display on the Tech 2.

Is the displayed value above the specified value?

Above 5

counts

Go to Step

Go to Step 9

1. Visually and physically inspect the throttle body,

intake manifold, EGR valve and the EGR feed pipe
for vacuum leaks.

2. Repair any vacuum leaks as necessary.

Did your inspection reveal a vacuum leak?

—

Verify repair

Go to Step

6E1–133

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0171 – System Too Lean (Bank 1)

(Cont'd)

Step

Yes

Value(s)

Action

Perform the ”Idle Air Control (IAC) Valve Check” and
correct any IAC problem as necessary.

Did this test isolate a problem requiring repair?

—

Verify repair

Go to Step

Check the fuel for excessive water, alcohol, or other
contaminants (see Diagnosis in Engine Fuel for the
procedure) and correct the contaminated fuel condition
if present (see Engine Fuel).

Was the fuel contaminated?

—

Verify repair

Go to Step

1. Visually and physically inspect the ECM injector

grounds, power grounds and sensor grounds to
ensure that they are clean, tight, and in their proper
locations.

2. If a faulty ground condition is present, correct it as

necessary.

Did your inspection reveal a condition requiring repair?

—

Verify repair

Go to Step

Perform the procedure in ”Fuel System Pressure Test”
and repair fuel system problem if necessary.

Did the test isolate a condition requiring repair?

—

Verify repair

Go to Step

Perform the ”Evaporative Emissions Control (EVAP)
Canister Purge Valve Check” and repair EVAP system
problem if necessary.

Did the test isolate a problem?

—

Verify repair

Go to Step

1. Visually and physically inspect the intake manifold,

injector O–rings, EGR adapter, EGR valve and the
EGR feed pipes for vacuum leaks.

2. Repair any problem that is found.

Did your inspection reveal a problem?

—

Verify repair

Go to Step

Visually and physically inspect the Bank 1 exhaust
manifold for leaks and loose or missing hardware and
correct any problem found.

Did your inspection reveal a problem?

—

Verify repair

Go to Step

Perform the ”Injector Balance Test,” and correct any
problem found (refer to Fuel Metering System).

Did the test isolate a problem?

—

Verify repair

Go to Step

1. Visually and physically inspect the Bank 1 HO2S 1

to ensure that it is installed securely and that the
Bank 1 HO2S 1 pigtail and wiring harness are not
contacting the exhaust or otherwise damaged.

2. If a problem is found, correct it as necessary.

Did your inspection reveal a problem?

—

Verify repair

Refer to

Diagnostic

Aids

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