Powertrain Controls - ECM/PCM

Code 65 Diagnostic Chart (Part 1 Of 2):

Code 65 Diagnostic Chart (Part 2 Of 2):

Injector Wiring Schematic:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) has two injector driver circuits, each of which controls a pair of injectors (1 and 4 or 2 and 3). The PCM monitors the current in each driver circuit by measuring voltage drop through a fixed resistor and is able to control it. The current through each driver is allowed to rise to a "peak" of 4 amps to quickly open the injectors, and is then reduced to 1 amp to "hold" them open. This is called "peak and hold." if the current can't reach a 4 amp peak, DTC 65 is set as noted below. This DTC is also set if an injector driver circuit is shorted to voltage.

DTC 65 WILL SET WHEN
^ 4 amp injector driver current not reached on either circuit.
^ Battery voltage greater than 9 volts.
^ injectors commanded "ON" longer than a calibrated pulse width.
^ Above conditions met for 10 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
Malfunction Indicator Lamp (MIL) illuminates.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

Part 1
1. This step determines if DTC 65 is the result of a hard failure or an intermittent condition.
2. Tests PCM and harness wiring to the injector connectors.
3. Tests for open or shorted injector. A shorted injector will not cause DTC 65.
4. Results of Step 2 will determine which branch to follow on Page 2 of diagnostic flow chart.
5. Checks remainder of circuits from injectors to PCM as both harnesses were confirmed OK in Step 2.

Part 2
6. This checks for short to voltage in injector driver circuits. It is necessary to crank the engine to assure voltage to CKT 120.
7. Determines whether injector driver CKTs 467 and 468 are shorted to ground.

DIAGNOSTIC AIDS
Open CKTs 467, 468 or CKT 467 or 468 shorted to voltage will cause DTC 65 and will also cause a misfire due to an inoperative pair of injectors.