P22C4 code meaning
O2 Sensor Pumping Current Trim Circuit High (Bank 2 Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P22C4 means
P22C4 is the high fault on the trim circuit of the bank 2 downstream wide-band probe. In Ford's key-on check of NTK label resistors, an estimated resistance that is too low means the line is shorted to power, which sets the trim-high code (P2631 for the bank 2 front probe); the stored resistor rank then stays in use. On Bosch-type probes a raised trim voltage looks much like an open: Saab and VW both trip their front trim code above 4.81 V, so makers may sort this fault into the open-circuit code. No maker documents P22C4 publicly, and GM's bank 1 slot P22B7 serves a NOx sensor oxygen ceiling with no bank 2 counterpart. Typical causes are a short to the heater feed or a damaged plug. P22C2 is the open, P22C3 the low case. The lamp lights.
P22C4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P22C4
- Check engine light
- Bank 2 downstream lambda slightly off; heater codes may accompany it
Common causes of P22C4
- Most likelyTrim wire shorted to the heater supply or another positive feed
- PossibleHeat- or water-damaged sensor plug bridging the trim pin
- Less likelyInternally shorted label resistor in the sensor connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank2 sensor2Oxygen sensor wiringECM
What each part of P22C4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| C4 | The exact fault in that area. |
What to do next
- Note P22C4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P22C4
What does P22C4 mean?
P22C4 means "O2 Sensor Pumping Current Trim Circuit High (Bank 2 Sensor 2)". P22C4 is the high fault on the trim circuit of the bank 2 downstream wide-band probe. It is a generic code, so it means the same on every make.
Is it safe to drive with P22C4?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P22C4 fail an emissions test?
Yes, it can. P22C4 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P22C4 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P22C4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.