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Tech Tips

Article Title: Trouble Code 332 Diagnosis
Contributed By: latechsho

Generic PFE/DPFE system fault tests

NOTE: This test step verifies if the DTC is due to an intermittent or a hard fault.

  • Perform KOEO and KOER Self-Test if you have not already done so and make note of all codes recieved in KOEO, Continuous Memory and KOER modes. If unable to run KOER due to a "No Start" or "Stall", do not continue with this step.
  • If an EGR fault exists at the time of this test(hard fault), then an EGR DTC should also be recieved in KOEO or KOER or both depending on the DTC. If the EGR DTC is NOT recieved in KOEO or KOER but only retrieved from Continuous Memory, this could be due to an intermittent EGR system fault which occurred sometime in the past.
  • Are there any EGR DTC's output in KOEO or KOER Self-Test (Ignore Continuous Memory DTC'satend of KOEO)?

If EGR DTC's exist from KOEO or KOER then a hard fault is indicated. Return to diagnostic routines trouble code index and Refer to the tests relevant to the DTC(s) in question.

If EGR DTC's do NOT exist from KOEO and KOER tests then an intermittent fault is indicated. Procede as follows:
  • Key off
  • Conduct a thorough visual inspection of the PFE/DPFE system for any potential failures. Use the following check list for possible causes:
    --Obvious physical damage
    --Loose connectors
    --Pushed out connector pins
    --Corroded connector contacts
    --Damaged wiring insulation
    --Incorrect harness routing
    --Road salt or rust accumulation
    --Damaged vacuum hoses
    --Incorrect vacuum hose routing
    --EVR solenoid filter contamination
    --Vacuum hose restriction
    --Road splash or icing
    --Incorrect service parts
  • Does the EGR system visual inspection reveal a potential failure?

If visual inpection does reveal a potential failure, service the fault as necessary. Clear the continuous memory codes. Rerun tests.

If visual inspection does NOT reveal a potential failure, reconnect all components and procede to code specific test

Code Specific Test Procedure
DTC 332 - Insufficient EGR flow detected

Possible causes:

  • EGR valve sticking closed
  • EGR valve diaphragm leaks
  • EVR solenoid sticking closed
  • Loss of vacuum to or from EVR
  • Open in EVR VPWR or driver circuits
  • Leak or restriction in PFE/DPFE signal hoses

To diagnose:
  • Key off
  • Connect a vacuum pump to the EGR valve.
  • While observing the EGR valve, slowly apply 34kPa (10 in-Hg) vacuum.
  • Note:EGR valve should begin to open with a very small amount of vacuum, approximately 3 to 5kPa (1-1.5in-Hg). EGR valve should remain open with vacuum applied or else vacuum diaphragm could be leaking if the valve closes immediately.
  • Does the EGR valve open smoothly and hold vacuum?

If EGR valve does NOT open smoothly and hold vacuum, Remove and Inspect the EGR valve for signs of diaphragm damage or leakage, contamination, unusual wear, carbon deposits, binding, and other damage. Service as necessary (including cleaning the unit with carb/throttle body cleaner). Clear continuous memory codes. Rerun tests.

If EGR valve does open smoothly and hold vacuum inspect EVR solenoid hoses.
  • Disconnect EVR vacuum hoses
  • Verify that hoses are clear of any obsructions, properly routed and will hold vacuum.
  • Are EVR vacuum hoses in good condition?

If not service vacuum hoses as necessary (generally replacement). Clear continuous memory and rerun tests.

If EVR vacuum hoses ARE in good condition reconnect EVR hoses and inspect PFE/DPFE signal line(s).
  • Disconnect PFE/DPFE signal hoses at the sensor.
  • Inspect sensor and signal line(s) for any signs of contamination, obstruction or leaks.
  • Is there a fault indicated?

If so isolate fault and service as necessary. Clear continuous memory codes and rerun tests.

If not reconnect all components and inspect EVR solenoid.

Note: The contents of this test procedure involve using a breakout box. More than likely you will not have access to one of these. If you find yourself in this situation you have options, but the inexperienced mechanic should probably not try to be creative with this test. Either have the EVR solenoid tested somewhere with the proper equipment or take the chance on it being bad and purchase a new one.

  • Key off
  • Disconnect ECU harness connector. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
  • Install breakout box and connect ECU to breakout box.
  • Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
  • Run engine to operating temperature and stabilized idle.
  • Jump test pin 40 to test pin 33 at the breakout box which should turn ON the EVR solenoid.
  • While reading the vacuum gauge, tap the EVR solenoid, wiggle the solenoid connector and solenoid vehicle harness. Look for a sudden drop in vacuum reading as you perform each action.
  • Is there a fault indicated?

If so, isolate and service fault as necessary. Reconnect all components, clear continuous memory, and rerun tests.

If not, test procedures are unable to duplicate and/or identify fault at this time.