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Hard Or Intermittent Trouble Code E39: Notes

NOTE: Following procedure is designed to account for intermittent codes. If no malfunction is uncovered using this procedure, it will indicate that DFI system is okay at this time.

The ECM completes circuit for VCC solenoid by grounding circuit No. 422. Grounding this circuit allows solenoid to energize and supply oil pressure to viscous converter clutch.

Code indicates that ECM is seeing engine speed at greater RPM than would be expected with VCC engaged. Possible causes of this condition are: Defective VCC solenoid, defective VCC brake switch, defective wiring, terminals, etc., ECM not able to process signals properly, or defective VCC unit.

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).
  1. To begin diagnosis, connect test light to circuit No. 422 pin F) on ALDL connector. With VCC disengaged (ECM not grounding circuit No. 422), test light should see 12 volts and light.
  2. If test light lights, then power is being supplied through VCC brake switch. While in output cycling, circuit No. 422 should go between 12 volts and 0 volts every 3 seconds. If test light does not flash, transmission should be checked for short circuit. If resistance between pins A and D is less than 15 ohms, solenoid or wires are shorted and should be repaired. This low resistance through transmission may have damaged ECM, therefore, after repairs have been made, check output of ECM in output cycling. If resistance is greater than 15 ohms, then circuit No. 422 should be checked for open to ECM. If wire is okay, check for faulty ECM connector or faulty ECM.
  3. If test light goes on and off every 3 seconds, then ECM and wiring are okay. Fault could be mechanical problem in transmission, therefore, road test should be performed. While crowding" the throttle at 55 MPH, gently tap brake pedal and note engine RPM in data parameter "P.1.1". RPM should increase approximately 200 RPM as VCC is disengaged. If RPM reading does not increase, VCC has failed to engage and should be diagnosed.
  4. If test light does not light on circuit No. 422, then there must be an open between ALDL connector and battery. First use switch tests to check VCC brake switch for proper operation.
  5. If VCC brake switch passes switch test code "E.7.1", then voltage on circuit No. 420 should be checked at transmission. If test light does not light, circuit No. 420 is open. If test light between circuit Nos. 420 and 422 does not light with pin F jumpered to ground, then circuit No. 422 is open. If test light does light, then open must exist either at transmission connector terminals or inside transmission itself.
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