P1200

DTC P1200 Injector Control Circuit:

DTC P1200 Injector Control Circuit (continued):

Fuel Injector Circuit:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) controls the fuel injector control circuit using a General FET Driver (GFD). The GFD has the ability to detect an electrical malfunction on any of the injector ignition feed or control circuits. If an electrical malfunction is detected, the GFD signals the PCM -to set DTC P1200.

CONDITIONS FOR SETTING THE DTC

^ An incorrect voltage level is being detected on an injector driver circuit.

^ Above condition for over 5 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the first trip in which the diagnostic runs and fails.

^ If equipped with traction control, the PCM will command the EBTCM via serial data (CKT 800) to turn OFF traction control and illuminate the TRACTION OFF lamp.

^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

^ The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS

The misfire history counters may be useful in determining which injector circuit is faulty. If DTC P0300 was set, look at the Misfire Hist # display for each cylinder. The largest value stored in the misfire history counters will indicate the location of the faulty injector circuit or injector.

Check for the following conditions:

^ Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

Reviewing the Fail Records vehicle mi]eage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. The Misfire Current Cyl # and Misfire History Cyl # counters can be used to isolate the problem cylinders.

4. Checks for faulty injector control or ignition feed wiring.

9. Checks for a fault in the injector ignition feed circuit.

10. Checks for a short to ground in the injector control circuit.

11. Checks for an open in the injector control circuit.

18. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.