Opel Frontera UE. Manual - part 218

6E1–170

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0401 EXHAUST GAS RECIRCULATION

(EGR) FLOW INSUFFICIENT DETECTED

D06RX113

Circuit Description

The engine control module (ECM) tests the exhaust gas
recirculation (EGR) system during deceleration by
momentarily commanding the EGR valve to open while
monitoring the manifold absolute pressure (MAP) sensor
signal. When the EGR valve is opened, the ECM monitors
the change in MAP input signal. The ECM compares the
MAP change to a RPM vs. BARO table. When the ECM
interprets the change in MAP to be out of limits, the ECM
will set DTC P0401. The number of test samples required
to accomplish this may vary according to the severity of
the detected flow error.
Normally, the ECM will only allow one EGR flow test
sample to be taken during an ignition cycle. To aid in
verifying a repair, the ECM allows twelve test samples
during the first ignition cycle following a Tech 2 ”Clear Info”
or a battery disconnect. Between nine and twelve
samples should be sufficient for the ECM to determine
adequate EGR flow and pass the EGR test. DTC P0401
is a type A code.

Conditions for Setting the DTC

No TP sensor, VSS, EVAP Purge, IAC, IAT sensor,
MAP sensor, EGR Pintle Position sensor, ECT sensor,
misfire DTCs set.

Barometric pressure is above 72 kPa.

Engine coolant temperature is greater than 60

(140

F).

System voltage is between 11.5 and 16 volts.

Vehicle speed is greater than 23 km/h (14 mph).

IAC position is steady, changing less than 5 counts.

A/C clutch status is unchanged.

Start Test

TP angle is less than 0.8%.

EGR duty cycle is less than 1%.

MAP is steady, changing less than 1 kPa.

Engine speed is between 1200 RPM and 2000 RPM.

Compensated MAP between 10.3 kPa and 49.8 kPa.

Run Test

Delta MAP is recorded during valve open conditions.

EGR valve is ramped over a time interval.

Run Test will be aborted if any of the following are true:

Vehicle speed changes by greater than 16 km/h
(10mph).

Engine RPM changes by greater than 100 rpm.

EGR is opened less than 95% of the commanded
amount.

During the Start Test and the Run Test, the EGR is closed
then opened. The associated change in MAP is
compared with the ECM’s expected change value. If the

6E1–171

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

difference between the two values exceeds the ECM’s
internal limit, a Diagnostic Trouble Code P0401 will set.
DTC P0401 is a type A code.

NOTE: Several deceleration cycles will be necessary to
run a sufficient number of EGR flow tests to determine a
”pass” or ”fail” condition.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate
the first time the fault is detected.

A history Diagnostic Trouble Code is stored.

A history Diagnostic Trouble Code will clear after 40
consecutive warm up cycles without a fault.

The MIL will turn OFF after three consecutive ignition
cycles in which the diagnostic runs without a fault.

Conditions for Clearing the DTC

The MIL will turn OFF after three consecutive ignition
cycles in which the diagnostic runs without a fault.

A history Diagnostic Trouble Code will clear after 40
consecutive warm up cycles without a fault.

Diagnostic Trouble Codes can be cleared by using the
Tech 2.

Diagnostic Aids

Check for the following conditions:

Poor connection or damaged harness – Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the Actual EGR Position display on the
Tech 2 while moving connectors and wiring harnesses
related to the EGR valve. A change in the display will
indicate the location of the fault.

Ensure EGR valve is correctly mounted. See
On–Vehicle Service.

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.

NOTE: If the EGR valve shows signs of excessive heat,
check the exhaust system for blockage (possibly a
plugged catalytic converter) using the ”Restricted
Exhaust System Check.”

6E1–172

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0401 – Exhaust Gas Recirculation Flow Insufficient Detected

Step

Action

Value(s)

Yes

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

—

Go to Step 2

Go to OBD

System

Check

1. Start the engine.
2. Monitor the MAP signal with a Tech 2 while idling.
3. While idling, depress the accelerator pedal about

halfway down and immediately let the engine return
to idle.

Did the MAP value on the Tech 2 show an immediate
large change?

—

Go to Step 4

Go to Step 3

Replace the MAP sensor.

—

Verify repair

—

1. Inspect the exhaust system for modification of

original installed parts or leaks.

2. If a problem was found, repair exhaust system as

necessary.

Was a condition present that required repair?

—

Go to Step 7

Go to Step 5

1. Remove the EGR valve.
2. Visually and physically inspect the pintle, valve

passages and the adapter for excessive deposits or
any kind of a restriction.

3. If a problem if found, clean or replace EGR system

components as necessary.

Was a condition present that required repair?

—

Go to Step 7

Go to Step 6

1. Remove the EGR inlet and outlet pipes from the

exhaust manifold and the intake manifold.

2. Inspect the manifold EGR ports and the EGR inlet

and outlet pipes for a blockage caused by excessive
deposits or other damage.

3. If a problem is found, correct the condition as

necessary.

Was a condition present that required repair?

—

Go to Step 7

Refer to

Diagnostic

Aids

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

Tech 2 System Info Screen while operating the
vehicle as specified in ”Diagnostic Aids.”

3. Using a Tech 2, monitor “Diagnostic Trouble Code”

info for Diagnostic Trouble Code P0401 until the
Diagnostic Trouble Code P0401 test runs.

4. Note the test result.

Does the Tech 2 indicate Diagnostic Trouble Code
P0401 failed this ignition?

—

Repair

complete

6E1–173

X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0402 EXHAUST GAS RECIRCULATION

(EGR) EXCESSIVE FLOW DETECTED

D06RX113

Circuit Description

The Engine Control Module (ECM) closes the Exhaust
Gas Recirculation (EGR) system on engine start–up to
test for excessive (any) flow. If the ECM determines that
EGR flow occurred on start–up, in two consecutive trips,
then DTC P0402 will set. DTC P0402 is a type B code.

Conditions for Setting the DTC

Intake Air Temperature (IAT) is above 5

C (41

F).

Engine RPM is less than 500 RPM.

EGR Pintle Position if greater than 55 counts.

The above mentioned conditions must be met for 0.6
seconds during engine start–up on two consecutive trips.

Diagnostic Aids

Check for the following conditions:

Ensure EGR valve is correctly mounted. See
On–Vehicle Service.

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.

NOTE: If the EGR valve shows signs of excessive heat,
check the exhaust system for blockage (possible a
plugged catalytic converter) using the ”Restricted
Exhaust System Check.”

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