Code 65, Injector Current Low W Body: Notes

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

1. The following conditions must be present to set a Code 65:
   • The 4-amp injector current was not reached on each circuit.
   • Battery voltage greater than 9 volts.
   • Injectors pulsed "ON" longer than calibrated pulse width.
   • The above conditions met for 20 seconds.
2. Checks ECM and harness wiring to 3-terminal injector harness connector.
3. This tests for open injector harness or injector.
   NOTE: Although shorted harness or injector will not set a Code 65, problem should be corrected if discovered.
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 ECM.
6. Identifies cause of high resistance found in step 3). A shorted injector will cause Code 65.
7. This tests for grounded "peak and hold" jumpers. This condition allows injectors to pulse, but would not allow "peak and hold" operation as current would not flow through resistor in ECM.
8. This checks for short to voltage in injector driver circuits.
9. Determines if injector driver circuits No. 467 and 468 are shorted to ground.
10. This checks the output at the ECM to determine if circuits No. 467 and 468 are okay.
11. Checks for proper continuity of "peak and hold" jumpers circuits No. 887 and No. 888.