Circuit Description
The Powertrain Control Module (PCM) has four fuel injector driver circuits, each of which controls a fuel injector. The PCM monitors the current in each driver circuit and is able to control the driver circuit. The current through each driver can rise to a peak of 2 amps in order to quickly open the fuel injectors. The current can reduce to 1/2 amp to hold the fuel injectors open. This is called peak and hold. If the current cannot reach a 2-amp peak, a DTC is set. This DTC is also set if a fuel injector driver is shorted to voltage.
Conditions for Running the DTC
| • | Engine is running |
| • | Battery voltage is more than 9 volts. |
Conditions for Setting the DTC
| • | Injector current is less than 1 amps. |
| Or |
| Injector current is continuously high. |
| • | Above conditions met for 7 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) if a failure is detected during 2 consecutive key cycles. |
| • | The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tool Freeze Frame/Failure Records. |
Conditions for Clearing the MIL or DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed. |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool in order to clear the DTCs. |
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage will cause a DTC P0200 to set and will also cause a misfire due to an inoperative injector. A misfire DTC should also be set indicating which cylinder is inoperative.
Long term and short term fuel trims that are excessively high or low are a good indication that an injector is malfunctioning. Refer to Fuel Injector Balance Test to check for malfunctioning injectors.
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
-
This step determines if the DTC P0200 is the result of a hard malfunction or an intermittent condition.
-
This step tests the harness wiring and for the PCM control of the fuel injectors by using a fuel injector test lamp. If the tests lamp blinks, this indicates that the PCM and the wiring to the fuel injectors are OK. Using the Fuel Injector Coil Test will check if the fuel injectors are malfunctioning.
-
Whether the test lamp was ON steady or OFF while cranking the engine, this step narrows the malfunction down to just a few possibilities.
-
Because the test lamp was ON steady, the voltage to the fuel injector is OK, but the fuel injector driver circuit is grounded at all times. This step determines if the circuitry is shorted to ground or if the PCM is malfunctioning.
-
Reprogram the replacement PCM and perform the Crankshaft Position System Variation Learn Procedure. Refer to the latest Techline information for PCM programming.
-
This step determines if the voltage is available to the fuel injector. The voltage is supplied through the fuel pump relay so that the engine must be cranked in order for you to see voltage at the fuel injector.
-
This step determines if the fuel injector driver circuit is open or shorted to voltage or if the PCM is malfunctioning.
-
Since the voltage is supplied to the fuel injector on a single circuit before the fuel injector harness, the malfunction could only be a poor electrical connection or an open in the fuel injector harness. An open before the harness would result in a Cranks But Will Not Run complaint.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
2 | Attempt to start the engine. Will the engine start? | -- | ||||||||
Does DTC P0200 reset? | -- | Go to Diagnostic Aids | ||||||||
Does the fuel injector test lamp blink on all tests? | -- | |||||||||
Verify whether the fuel injector test lamp was OFF or ON steady in step 4 for the fuel injector connector that did not blink. Was the fuel injector test lamp ON steady while cranking the engine? | -- | |||||||||
Does the test lamp illuminate? | -- | |||||||||
7 |
Was a repair necessary? | -- | ||||||||
|
Important:: Program the replacement PCM.Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | ||||||||
Does the test lamp illuminate while cranking? | -- | |||||||||
Is the test lamp OFF while you crank the engine? | -- | |||||||||
Is the action complete? | -- | -- | ||||||||
12 |
Is a problem present? | -- | ||||||||
13 |
Is the action complete? | -- | -- | |||||||
14 | Repair the following condition(s) in the fuel injector driver circuit:
Is the action complete? | -- | -- | |||||||
15 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||||||||
16 | Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
