P0989: Transmission Fluid Pressure Sensor/Switch E Circuit Low
What to do
Ask for a mechanical gauge reading rather than a scan tool figure, since the scan tool reads the sensor under suspicion. If the transmission is slipping too, assume genuine pressure loss until the gauge says otherwise.
What this code means
The fifth pressure sensor circuit reads below its valid electrical range, typically a short to ground. The distinction that governs the whole family applies: a circuit reading low is not the same as pressure being low, and only a mechanical gauge on the test port separates them.
Likely causes
Start here
- Wiring shorted to ground · moderate
- Faulty transmission fluid pressure sensor · moderate
- Low or degraded transmission fluid · easy
Less common
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0989.