DTC 65

Code 63,64,65 Chart:

Code 63,64,65 Wiring Diagram:

CIRCUIT DESCRIPTION:


Codes 63, 64, and 65 are EGR flow test failures. The ECM on a closed throttle coast down will cycle the solenoids "ON" and "OFF" individually and look for a resulting change in engine rpm and O2 sensor activity.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

If a code is set, inspect the EGR for damage. Disconnect the 4 wire connector at EGR. Install a fused jumper from the battery to terminal "D" of the EGR. Start and idle engine, and with a jumper, ground terminals "A," "B," & "C" one at a time. You should be able to note a change in engine rpm as the terminal is grounded. Terminal "A" should result in a small change and "C" in a large change.

NOTES:

If the digital EGR valve shows signs of excessive heat, a melted condition, check the exhaust system for blockage or possibly a plugged converter. A plugged exhaust may be do to a:

^ STUCK OPEN INJECTOR
^ GROUNED DRIVER CKT
^ POSSIBLE FAULTY ECM



DIAGNOSTIC AIDS:

An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check for Poor Connection or Damaged Harness Inspect ECM harness connectors for backed out terminals "BC2," "BC3," and "BD2," improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

Intermittent Test - If connections and harness check OK, connect a digital voltmeter from effected terminals to ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change.