P2A90 code meaning
Alternative Fuel Pump C Performance
Powertrain system Generic code P2Axx codes Check engine light
What P2A90 means
P2A90 marks pump C of the alternative fuel system as delivering too little. A third pump may belong to a further tank or, in Caterpillar's design US10060421B2, be one of several pumping elements driven in sequence. Besides wear, cryogenic pumps have a typical weakness that Caterpillar's patent US9228574B2 describes: if the liquid at the inlet has warmed enough to form vapour, the pump cavitates and delivery stops, so centrifugal designs need a positive feed pressure. Short bursts of poor output after long parking, with warmer LNG in the tank, fit this picture; a permanent shortfall points to worn parts. The pump diagnosis in US20080302111A1 explains how a slow pressure rise reveals the loss. No manufacturer publishes P2A90; P2A87 to P2A8A cover pump C's stroke valve.
P2A90 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor3 to 10 hours
- Clears after repairAfter a drive cycle
Symptoms of P2A90
- Warning lamp on
- Weak pull or hesitation shortly after a long stop
- Gas pressure recovers slowly after heavy acceleration
Common causes of P2A90
- Most likelyVapour at the inlet of pump C after warm soak, causing cavitation
- PossibleWorn seals or valves in pump C
- Less likelyClogged inlet strainer or filter ahead of pump C
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Alt fuel pump cAlt fuel filter
What each part of P2A90 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| A | Area: hybrid propulsion. |
| 90 | The exact fault in that area. |
What to do next
- Note P2A90 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 P2A90
What does P2A90 mean?
P2A90 means "Alternative Fuel Pump C Performance". P2A90 marks pump C of the alternative fuel system as delivering too little. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A90?
Drive gently and only to a workshop. With P2A90 the car can go into limp mode (reduced power) to protect itself.
Will P2A90 fail an emissions test?
Yes, it can. P2A90 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 P2A90 to fix?
Difficulty: workshop only. A typical repair takes 3 to 10 hours of work. This is a job for a workshop.
Will P2A90 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.