Technical Description of OBD-II Trouble Code
Malfunction in Cylinder 1 Injector Circuit
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
P0201 indicates that the PCM has detected a fault in the injector or the wiring connected to the injector. The PCM monitors the injector and expects to observe a voltage that is pulled “low” or close to zero when the injector is activated.
When the injector is switched off, the PCM expects to see a voltage that is close to the battery voltage or “high”. If the expected voltage is not detected, the PCM will set this code. The PCM also monitors the resistance in the circuit and will set this code if the resistance is excessively low or high.
Potential Symptoms
The symptoms associated with this code are likely to include a misfire and a rough running engine, as well as poor acceleration. The MIL (Malfunction Indicator Lamp) will also be illuminated.
Causes
The possible causes of this code could be any of the following:
Faulty injector. This is typically the primary cause of this code, although it does not exclude the possibility of one of the other causes.
Open circuit in the wiring connected to the injector
Short circuit in the wiring connected to the injector
Defective PCM
Possible Solutions
First, use a DVOM (Digital Volt-Ohm Meter) to check the resistance of the injector. If the resistance is not within the specified range, replace the injector.
Check for voltage at the fuel injector connector. It should measure 10 volts or higher.
Visually inspect the connector for any signs of damage or broken wires.
Visually inspect the injector for any signs of damage.
If you have access to an injector tester, activate the injector and observe if it operates properly. If the injector operates as expected, it is likely that there is an open circuit in the wiring or a blocked injector. If you do not have access to a tester, try swapping the injector with another one and see if the code changes. If the code changes, replace the injector.
At the PCM, remove the driver wire from the PCM connector and ground the wire. (Ensure that you have identified the correct wire. If you are unsure, do not attempt this step) The injector should activate.
Replace the injector
