Code 65, Injector Current Low: Notes

PCM has 2 injector driver circuits, each controlling a pair of injectors (1 and 4 or 2 and 3). PCM monitors current of each injector driver circuit by measuring voltage drop through a fixed resistor. PCM is able to control voltage drop. Current through each driver is allowed to rise to peak of 4 amps, enabling injectors to open quickly; current is then reduced to one amp, holding injectors open. This is called "peak and hold". If current cannot reach a 4-amp peak, Code 65 is set. This code is also set if an injector driver circuit is shorted to voltage.

1. Following conditions must be present to set Code 65:
   • 4-amp injector current was not reached on each circuit.
   • Battery voltage greater than 9 volts.
   • Injectors pulsed on longer than calibrated pulse width.
   • Above conditions met for 20 seconds.
2. Checks PCM and harness wiring to 3-terminal injector harness connector.
3. This tests for open injector harness or injector.
4. Results of step 2) will determine which branch to follow on Code 65 flow chart (2 of 2).
5. Each harness was confirmed as being okay in steps 2) and 3). This test will check remainder of circuit from injectors to PCM.
   NOTE: Although shorted harness or injector (zero ohms) will not set a Code 65, problem should be corrected if discovered.
6. Identifies cause of high resistance found in step 3). A short or low resistance will not cause Code 65 but should be corrected.
7. This tests for grounded "peak and hold" jumpers. This condition would allow injectors to pulse, but it would not allow "peak and hold" operation as current would not flow through resistor in PCM.
8. This checks for short to voltage in injector driver circuits.
9. Determines if injector driver circuits are shorted to ground.
10. This checks output at PCM to determine if injector driver circuits are okay.
11. Checks for proper continuity of "peak and hold" jumpers circuits.