:  Dec 17, 2007



Overview

For information on the operation of the emissions systems, refer to relevant workshop manual section.

Inspection and Verification

. Verify the customer concern.

. Visually inspect for obvious mechanical faults.

Mechanical Electrical
  • Exhaust gas recirculation (EGR) pipes
  • Breather hoses
  • Positive crankcase ventilation valve
  • Fuel level
  • Fuel contamination/grade/quality
  • Throttle body
  • Fuse 5 of the battery junction box
  • Loose or corroded electrical connectors
  • Exhaust gas recirculation (EGR) valve
  • Engine control module (ECM)

. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

. Use the approved diagnostic system or a scan tool to retrieve any diagnostic trouble codes (DTCs) before moving onto the symptom chart or DTC index.
  Make sure that all DTCs are cleared following rectification.
Make sure that all DTCs are cleared following rectification.

Symptom Chart

:
  For a more comprehensive symptom chart, refer to workshop manual section 303-14 - Electronic Engine Controls

Symptom Possible cause Action
Difficult to start cold
  • Battery
  • Crankshaft position (CKP) sensor
  • Exhaust gas recirculation (EGR) valve stuck open
  • Fuel system
  • Evaporative emissions purge valve
For battery information, CKP sensor tests, fuel system and purge valve tests, refer to relevant workshop manual section. Check the EGR valve. Refer to the guided diagnostic routine on the approved diagnostic system.
Engine stalls soon after start
  • Breather system disconnected/restricted
  • ECM relay
  • MAF sensor
  • Ignition system
  • Air filter restricted
  • Air leakage
  • Fuel lines
Check the engine breather hoses, PCV, etc. Check the ECM relay operation. For MAF sensor, ignition system tests, air intake information and fuel line information, refer to relevant workshop manual section.
Poor throttle response
  • APP sensor malfunction
  • TP sensors
  • ECT sensor
  • MAF sensor
  • Transmission malfunction
  • Traction control event
  • Air leakage
  • Breather system disconnected/restricted
For APP, TP, ECT, MAF sensor tests, intake system checks and transmission information, refer to relevant workshop manual section. Check the breather system hoses, PCV, etc.

DTC index

:
  Generic scan tools may not read the codes listed, or may read only 5-digit codes. Match the 5 digits from the scan tool to the first 5 digits of the 7-digit code listed to identify the fault (the last 2 digits give extra information read by the manufacturer-approved diagnostic system).

:
  For a full list of ECM DTCs, refer to workshop manual section 303-14 - Electronic Engine Controls

DTC Description Possible cause Action
P040100 Exhaust Gas Recirculation A Flow Insufficient Detected
  • EGR pipe blocked
  • EGR valve incorrectly installed or loose
  • EGR valve stuck closed/blocked
  • EGR valve failure
Check the EGR pipes. Check the EGR valve installation, refer to relevant workshop manual section Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P048900 Exhaust Gas Recirculation Control Circuit Low
  • EGR valve power supply circuit high resistance
  • EGR valve power supply circuit: short circuit to ground
Refer to the guided diagnostic routine for this code on the approved diagnostic system.
P049000 Exhaust Gas Recirculation Control Circuit High
  • EGR valve drive circuit short circuit to power
Refer to the guided diagnostic routine for this code on the approved diagnostic system.