P289E code meaning
Cylinder 4 Ion Current Sense Circuit Low
Powertrain system Generic code P28xx codes Check engine light
What P289E means
P289E means the ion signal of cylinder 4 remains below the range the module expects. A ground fault on the line from coil 4, a plug whose insulator conducts the bias voltage away, or a coil that has stopped generating that voltage are the main suspects. In Saab's T7 four-cylinder cassette, cylinders 3 and 4 share one detector that pulses engine module pin 6; Saab notes that a short to ground on such a combustion line produced only misfire codes, while an open line was flagged as P1334. A dedicated low code for cylinder 4 separates this case. Since cylinder 4 is also the start partner of cylinder 1, a dead signal can affect synchronisation. The opposite reading is P289F.
P289E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P289E
- MIL with low ion signal on cylinder 4
- Possible start delay or misfire codes
- Power reduced by safety timing on cylinder 4
Common causes of P289E
- Most likelyIon signal line of cylinder 4 shorted to ground
- PossibleSpark plug insulator of cylinder 4 leaking the bias voltage
- PossibleBias voltage generation inside coil 4 failed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Spark plug cyl 4Ignition coil cyl 4Ion sense module
What each part of P289E 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. |
| 9E | The exact fault in that area. |
What to do next
- Note P289E 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 P289E
What does P289E mean?
P289E means "Cylinder 4 Ion Current Sense Circuit Low". P289E means the ion signal of cylinder 4 remains below the range the module expects. It is a generic code, so it means the same on every make.
Is it safe to drive with P289E?
Drive gently and only to a workshop. With P289E the car can go into limp mode (reduced power) to protect itself.
Will P289E fail an emissions test?
Yes, it can. P289E 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 P289E 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 P289E clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.