P28B1: The cylinder 9 ion current detection gives readings outside the normal range
The cylinder 9 ion current detection gives readings outside the normal range. It is usually the part, its wiring or a connector with poor contact.
| Code | P28B1 |
|---|---|
| System | Engine and transmission |
| Group | P28xx, Transmission and engine |
| Type | Generic: it means the same on every make |
How to read and clear P28B1 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P28B1 with its description and whether it’s confirmed, pending or permanent.
This code is usually stored by the gearbox control unit. If the car reports it over standard OBD, you read it for nothing with FREE; to read it straight from the gearbox control unit, with its description and clearing, you need PRO.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P28AD The cylinder 8 ion current detection gives readings outside the normal range
- P28AE The cylinder 8 ion current detection gives a lower signal than normal
- P28AF The cylinder 8 ion current detection gives a higher signal than normal
- P28B0 The cylinder 9 ion current detection has an electrical fault
- P28B2 The cylinder 9 ion current detection gives a lower signal than normal
- P28B3 The cylinder 9 ion current detection gives a higher signal than normal
- P28B4 The cylinder 10 ion current detection has an electrical fault
- P28B5 The cylinder 10 ion current detection gives readings outside the normal range
What does code P28B1 mean?
The cylinder 9 ion current detection gives readings outside the normal range. It is usually the part, its wiring or a connector with poor contact.
How do you clear P28B1?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P28B1 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
