P0201

DTC P0201 Injector 1 Control Circuit




Circuit Description
The powertrain control module (PCM) has six individual injector driver circuits. Each controls an injector. When a driver circuit is grounded by the PCM, the injector is activated. The PCM monitors the current in each driver circuit. The voltage on each driver is monitored to detect a fault. If the voltage is not what the PCM expects to monitor on the circuit, a DTC is set. This DTC is also set if an injector driver is shorted to voltage or if there is an open circuit.

Conditions for Setting the DTC
- The battery voltage is more than 9 volts.
- The engine is turning, determined by 58X crankshaft position input signal.
- The injector voltage does not equal the ignition voltage when the injector is commanded OFF or the injector voltage does not equal 0 volts when the injector is commanded ON.
The above conditions are met for 5 seconds.

Action Taken When the DTC Sets
- The PCM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.
- The PCM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.

Conditions for Clearing the MIL/DTC
- The PCM will turn OFF the MIL on the third consecutive trip cycle in which the diagnostic has been run and the fault is no longer present.
- A history DTC P0201 will clear after 40 consecutive warm-up cycles occur without a fault.
- DTC P0201 can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids
An injector driver circuit that is open or shorted to voltage will cause a DTC P0201 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC will 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 faulty.
Use Fuel Injector Coil Test Procedure to check for faulty injectors.

Steps 1 - 8:

Steps 9 - 15:

Test Description
The number(s) below refer to the step number(s) on the Diagnostic Chart.
3. This step determines if DTC P0201 is the result of a hard failure or an intermittent condition.
5. A special injector test connector is provided so that the injectors can be electrically tested without removal of the manifold. The test connector can be identified by the blue connector lock which is tethered to the wiring harness. If the light for cylinder 1 is ON steady before cranking the engine as well as while cranking the engine, then the injector driver circuit is shorted to ground.
If the test light blinks while cranking, the PCM and the wiring to the injectors are OK. The Fuel Injector Coil Test Procedure will check if the injectors are faulty.
7. Because the test light was ON steady, voltage to the injector is OK, but the driver circuit is grounded at all times. This step determines if the circuit is shorted to ground or the PCM is faulty.
9. The reading should be about 12-14 ohms.
10. Locating the open in the harness or in the injector will require removal of the manifold to provide access.