DIAGNOSTIC TROUBLE CODE (DTC) - P1402 ELECTRIC EXHAUST GAS RECIRCULATION BLOCKED

Knowing The Circuit

  • By any chance if high combustion temperatures are created by oxides of nitrogen then An Electric Exhaust Gas Re-circulation (EEGR) system which is the chief feature of this system will be boosted to counter this.
  • This is done by supplying small amounts of exhaust gases back into the combustion chamber.
  • Combustion temperatures are minimized as soon as the air/ fuel mixture dilutes the exhaust gases.
  • The EEGR valve has been specially designed to generate exhaust gases to the engine without using intake manifold vacuum.
  •  This valve regulates exhaust flow entering the intake manifold from the exhaust manifold through an orifice with an ECM controlled pintle.
  • The pintle position is monitored by the ECM using inputs from the Throttle Position (TP) and the Manifold Absolute Pressure (MAP) sensor.
  • This task over, the ECM then directs the EEGR valve to operate as necessary by controlling an ignition signal through the ECM.
  • The ECM further monitors the results of its command through a feedback signal.
  • The desired EEGR position can be checked with the help of a scan tool.
  • A voltage signal representing the EEGR valve pintle position is sent to the ECM by a 5 volt reference and a ground to the EEGR valve.
  • The scan tool can also be used here to note the feedback signal which is the actual position of the EEGR pintle.
  • The correct EEGR position should always be close to the commanded or Desired EEGR position.
  • This Diagnostic Trouble Code (DTC) is capable of identifying an open or short circuit.

 

Conditions for Setting the DTC

·         Engine Coolant Temperature (ECT) > than 80°C (176°F).

·         Intake Air Temperature (IAT) > than 15°C (59°F).

·         Manifold Absolute Pressure > than 75kPA.

·         The EEGR > than 3%.

·         Mass Air Flow is <=92 and >= 157mg/tdc.

·         Engine Speed <=2,500and >=2,900rpm.

·         DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0300, P0335, P0336, P0341, P0342, P1671, P1672, P1673 are NOT SET.

·         EEGR is disabled.

What happens when DTC sets?

When will DTC clear?

1) The Malfunction Indicator Lamp (MIL) will start glowing

1) The MIL will turn off after four successive ignition cycles in which the diagnostic runs faultlessly.

 

2) The ECM will record operating conditions at the time when the diagnostic fails the information of which will be stored in the Freeze Frame and Failure Records will buffer

2) A history DTC will clear automatically after 40 consecutive warm-up cycles without a fault.

 

3) A history DTC will be stored.

 

3) Scan tools clear every DTC

 

DIAGNOSTICS TOOLS

 

  • Moisture related with exhaust systems might result in the EEGR valve to freeze and malfunction in cold weather occasionally.
  •  This problem will be solved when the vehicle is taken to any warm shop for repairs and the affected part duly repaired.
  • The error in DAEWOO M-198 BL2 can be easily noted by comparing the Actual EEGR and the desired EEGR positions on a cold vehicle with a scan tool.
  • Note the Engine Coolant Temperature (ECT) and then check the Freeze Frame data to ensure that the DTC was set when the vehicle was cold.

 

                                                                    TABULATION OF THE TASKS TO BE DONE

 DTC P1402 - Electric Exhaust Gas Recirculation Blocked

Step

Task

Value(s)

R  E  S

U  L  T

1

Undertake an EOBD System Check.

Work Done?

-

IF  YES       THEN

Follow Step 2

IF  NO      THEN

Go to "On-Board Diagnostic System Check"

2

  1. Start the engine.
  2. Let the engine keep running.
  3. Fix the scan tool.
  4. Take the electric exhaust gas recirculation (EEGR) valve to the value stated.

Do you observe that the engine shows a tendency to stall?

50%

IF  YES       THEN

Follow Step 5

IF  NO    THEN

Follow Step 3

3

  1. Take the ignition switch to LOCK mode.
  2. Dissociate the EEGR valve assembly.
  3. Examine the a) EEGR valve b) passages c) pipe for a restriction or tampering and mend as needed.

Task complete?

-

IF  YES       THEN

Follow Step 5

IF  NO      THEN

Follow Step 4

4

Substitute the EEGR valve.

 

Substitution Over?

-

IF  YES       THEN

Follow Step 5

-

5

  1. Restart the engine.
  2. Dissociate the battery for the specified time.
  3. Run the vehicle to the specified value.
  4. Let the vehicle decelerate to the given value after releasing the throttle.

Do you notice that the EEGR Decel Filter Value is lesser than the value given?

10 seconds

60mph

(97km/h)

20mph

(32km/h)

0mph

IF  YES       THEN

Follow Step 3

IF  NO     THEN

Follow Step 6

6

      1) Unset the DTCs, taking a scan tool.

2) Start the engine and idle at normal operating temperature.

3) Run the vehicle within the parameters needed for setting this DTC as mentioned in the supporting text.

Does the scan tool indicate that this diagnostic has been run and passed?

-

IF  YES            THEN

Follow Step 7

IF  NO      THEN

Follow Step 2

 

 

7

Check if any additional DTCs are set.

 

Do you see any undiagnosed DTC still being displayed?

 

IF  YES       THEN

Go to Applicable DTC table

IF  NO      THEN

The System of your car is fine.