6E1–138
X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DIAGNOSTIC TROUBLE CODE (DTC) P0201 INJECTOR CIRCUIT
MALFUNCTION – CYLINDER 1
D06RX120
Circuit Description
The engine control module (ECM) has four individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The ECM 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
ECM 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
D
The battery voltage is more than 9 volts.
D
Engine is running.
D
Fuel pump is ON.
D
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.
D
The above conditions are met for 5 seconds.
Action Taken When the DTC Sets
D
The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
D
”Open Loop” fuel control will be in effect.
D
The ECM 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
D
The ECM 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.
D
A history Diagnostic Trouble Code P0201 will clear
after 40 consecutive warm–up cycles occur without a
fault.
D
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.