P0201
DTC P0201 Injector Circuit Malfunction - Cylinder 1
Circuit Description
The powertrain control module (PCM) has four 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 PCM measures a voltage drop through a fixed resistor and controls it. 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 Diagnostic Trouble Code is set. This Diagnostic Trouble Code is also set if an injector driver is shorted to voltage. DTC P0201 is a type A code.
Conditions for Setting the DTC
- The battery voltage is more than 9 volts.
- Engine is running.
- Fuel pump is ON.
- 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.
- "Open Loop" fuel control will be in effect.
- The PCM will store conditions which were present when the Diagnostic Trouble Code 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 Diagnostic Trouble Code P0201 will clear after 40 consecutive warm-up cycles occur without a fault.
- Diagnostic Trouble Code P0201 can be cleared by using the Scan Tool's "Clear Info" function.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage will cause a Diagnostic Trouble Code P0201 to set.
It will also cause a misfire due to an inoperative injector. A misfire Diagnostic Trouble Code 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 - 6:
Steps 7 - 14:
Steps 15 - 16:
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart:
3. This step determines if Diagnostic Trouble Code P0201 is the result of a hard failure or an intermittent condition.
5. This step tests the harness wiring and PCM control of the injectors using a test light.
The fuel injector test connector is a gray 5 pin connector at the right rear of the valve cover. It can be identified by a blue connector lock which is tethered to the harness.
J 39021-45 is a test light with one light for each cylinder. The test light fits on the injector test connector. If the test light is ON steady before cranking the engine as well as while cranking the engine, then the injector driver circuit is shorted to voltage.
If the test light blinks, the PCM and the wiring to the injectors are OK. 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.
13. Normal injector resistance is slightly more than if tested directly at the injector because it includes resistance of the harness wires. The normal value is about 13.5 ohms.