P0202-FUEL INJECTOR 2 CIRCUIT

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The fueling strategy for NGC requires potentially three fuel pulses per cylinder per cycle. The first pulse is delivered starting at a programmed angle soon after the intake valve closes, for specified time duration. This is for two reasons, one to prevent any fuel from this pulse being delivered in the previous cycle and second to allow fueling to begin as early as possible in the current cycle. The second pulse is delivered for a specified time and is set to end at a programmed angle. The pulse must not extend past the end angle. There can be a separate value for each cylinder under the same operating conditions. This is done for two reasons, one to prevent any fuel from this pulse being delivered during the intake/exhaust valve overlap period, which tends to cause elevated emission levels. Also, allowing fuel to enter each cylinder at a slightly different angle tends to reduce any fuel pressure standing waves in the fuel rail. If the desired total fuel pulse-width increases, a third fuel pulse must be delivered. The third pulse, if necessary, is delivered for a specified time and must end at a programmed angle before the valve closes again. The third pulse in the cycle is controlled by its ending angle. This is also for two reasons, one to prevent any fuel from this pulse being delivered in the next cycle and second to allow fueling to end as late as possible in the current cycle. At high engine speeds, one or more of the pulses may be dropped from the fueling strategy.

• When Monitored:

  With battery voltage greater than 10 volts. Auto Shutdown Relay energized. Engine speed less than 3000 rpm.

• Set Condition:

  The PCM monitors the continuity of the injector circuits as well as the voltage spike created by the collapse of the magnetic field in the injector coil. Any condition that reduces the maximum current flow or the magnitude of the voltage spike can cause this DTC to set.

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Diagnostic Test

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

NOTE: Review Freeze Frame information. Operate the vehicle under conditions similar to which the DTC was set.

• Go To 2

• Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

NOTE: The resistance of the circuit will vary according to the temperature of the injector coil. Use the table below to determine the resistance range of the injector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

• Go To 7

• Go To 3

• Repair as necessary.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Go To 4

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

• Go To 5

• Repair the excessive resistance or short to ground in the (F142) ASD Relay Output circuit.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

• Go To 6

• Repair the open in the (K12) Injector Control No.2 circuit.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Repair as necessary.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Replace the Fuel Injector 2 in accordance with the Service Information.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Repair the short to ground in the (K12) Injector Control No.2 circuit.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Go To 8

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

• Repair as necessary.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

• Replace and program the Powertrain Control Module per Service Information.
• Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)