What does it mean?
This diagnostic trouble code (DTC) is a generic powertrain code, meaning it applies to vehicles equipped with OBD-II. Although generic, specific repair steps may vary by make/model.
In sequential fuel injection, the PCM (Powertrain Control Module) controls each injector individually. Battery voltage is supplied to each injector from, typically, the Power Distribution Center (PDC) or another fused source.
The PCM powers the ground circuit of each injector using an internal switch called a “driver.” The PCM monitors each driver circuit for faults. For example, when a fuel injector is commanded “off” by the PCM, it expects to see high voltage on the driver ground circuit. Conversely, when a fuel injector is commanded “on” by the PCM, it expects to see lowered voltage on the driver circuit.
If it doesn’t see this expected condition on the driver circuit, P0200 or P1222 may set. Other fuel injector circuit fault codes may also be set.
Symptoms
Symptoms of a P0200 DTC may include:
MIL (Malfunction Indicator Lamp) illumination
Engine misfires at idle or highway speed
Engine may start and stall or not start at all
Cylinder misfire codes may be present
Causes
Potential causes of a P0200 code include:
Open or shorted injector
Injector with low internal resistance (essentially a working injector that’s out of specifications)
Driver circuit grounded
Open driver circuit
Driver circuit shorted to voltage
Wiring harness intermittently shorting against underhood components
Possible Solutions
1. If you have multiple misfire/injector codes, a good first step is to unplug all fuel injectors, then turn the ignition on, engine off (KOEO). Check for battery voltage (12 Volts) on one wire of each injector connector. If all are missing, check for ground continuity on the voltage circuit using a test light connected to the positive battery and probe each voltage supply. If it lights up, there’s a short to ground on the voltage supply, causing a short circuit. Obtain a wiring diagram and repair the short on the voltage supply and restore proper battery voltage. (Remember to check for a blown fuse and replace if necessary). NOTE: It’s possible for one injector to short the entire battery supply voltage to all injectors. So, if you’ve lost voltage to all injectors, replace the blown fuse and plug in each injector one by one. If the fuse blows, the last injector you plugged in is shorted. Replace it and retest. If only one or two battery supplies are missing, it’s more likely a shorted battery voltage supply in the individual injector’s wiring harness. Inspect and repair if necessary.
2. If battery voltage is supplied to each injector harness, the next step is to obtain a Noid light to check injector driver operation. A Noid light plugs into the injector harness in place of the fuel injector and flashes rapidly when the injector driver is operating. Check each fuel injector connector. If the Noid light flashes rapidly, suspect the injector. Ohm each fuel injector if you have a resistance specification. If the injector is open or resistance is higher or lower than specification, replace the fuel injector. If the injector tests okay, the problem is likely an intermittent wiring issue. (Remember, a fuel injector may work correctly when cold but open when hot, or vice versa. So it’s best to perform these checks when the problem occurs). Check the wiring harness for any chafing, or the injector connector for loose pins or a broken lock. Repair if necessary and retest. Now, if the Noid light doesn’t flash, there’s a problem with the driver or driver circuit. Unplug the PCM connector and ohm the fuel injector driver circuits. Any resistance means there’s a problem. Infinite resistance indicates an open in the circuit. Find and repair it, then retest. If you find no issues with the harness and there’s no fuel injector driver operation, check the PCM’s powers and grounds. If they’re correct, the PCM may be at fault.