P2628 code meaning
O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 1)
Powertrain system Generic code P26xx codes Check engine light
What P2628 means
With P2628 the trim input of the front wide-band probe on bank 1 lies above its permitted range. Ford's 2020-23 gasoline summary reserves it for NTK probes, where the interface chip reports the resistor line shorted to battery voltage. In GM's 2005 table for the Honda-sourced 3.5 L V6 it is the opposite end of P2627: the label resistor voltage drops under 0.29 V for 5 s. GM diesels apply it to the NOx sensor oxygen value downstream of the turbine; the 2020 table counts readings above 27 percent, i.e. more oxygen than air, in 100 of 200 samples and only while exhaust pressure is plausible (type B). A trim value out of range skews the lambda value the probe reports, so the module stops trusting the probe. Low is P2627, open P2626, bank 2 high P2631.
P2628 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2628
- Check engine light
- Mixture control without probe feedback, higher consumption
- On diesels NOx-related codes and possible SCR warnings
Common causes of P2628
- Most likelyTrim line shorted to battery or another supply in the harness or plug
- PossibleWide-band probe or NOx sensor delivering an implausible value
- Less likelyExhaust leak ahead of the sensor drawing in outside air
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank1 sensor1Sensor calibration resistorNox sensorOxygen sensor wiring
What each part of P2628 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| 28 | The exact fault in that area. |
What to do next
- Note P2628 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 P2628
What does P2628 mean?
P2628 means "O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 1)". With P2628 the trim input of the front wide-band probe on bank 1 lies above its permitted range. It is a generic code, so it means the same on every make.
Is it safe to drive with P2628?
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 P2628 fail an emissions test?
Yes, it can. P2628 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 P2628 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2628 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.