P28A6 code meaning
Cylinder 6 Ion Current Sense Circuit Low
Powertrain system Generic code P28xx codes Check engine light
What P28A6 means
P28A6 describes an ion reading from cylinder 6 that never leaves the bottom of its range. Between sparks the system keeps a small voltage across the plug, and the hot gas of a normal combustion lets a measurable current pass; if that voltage leaks to ground through a damaged conductor, a cracked ceramic or carbon deposits, or the coil stops supplying it, the reading collapses. With no usable value, the module treats cylinder 6 as unmonitored and usually falls back to safe timing. When tracing the fault, the harness along the cam cover deserves a close look for heat damage and chafed spots. No manufacturer documents P28A6 publicly; P28A7 is the high-side code.
P28A6 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P28A6
- MIL with low ion signal on cylinder 6
- Misfires on cylinder 6 possibly unrecorded
- Engine noticeably weaker on safe timing
Common causes of P28A6
- Most likelyDamaged ion conductor of cylinder 6 leaking to ground
- PossibleCracked ceramic or heavy deposits on the cylinder 6 plug
- PossibleCoil 6 no longer supplies the measuring voltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Spark plug cyl 6Ignition coil cyl 6Ion sense module
What each part of P28A6 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 8 | Area: transmission. |
| A6 | The exact fault in that area. |
What to do next
- Note P28A6 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 P28A6
What does P28A6 mean?
P28A6 means "Cylinder 6 Ion Current Sense Circuit Low". P28A6 describes an ion reading from cylinder 6 that never leaves the bottom of its range. It is a generic code, so it means the same on every make.
Is it safe to drive with P28A6?
Drive gently and only to a workshop. With P28A6 the car can go into limp mode (reduced power) to protect itself.
Will P28A6 fail an emissions test?
Yes, it can. P28A6 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 P28A6 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P28A6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.