P27A5 code meaning
Electric/Auxiliary Transmission Fluid Pump B Control Circuit High
Powertrain system Generic code P27xx codes Check engine light
What P27A5 means
P27A5 sets when the control line of auxiliary pump B sits at a level that only a connection to a voltage source can explain. In practice the wire touches a powered conductor, or moisture links it to a neighbouring supply pin. No manufacturer documents P27A5 publicly. For pump A, GM's 2025 TCM tables call the equivalent P2799 and judge it by an impedance below 0.5 Ω from signal to a voltage source in 20 of 25 checks, carried out only while the relevant driver is active and supply voltage is between 9 and 15 V; it is a Type B fault. Depending on how the circuit is built, such a short can leave pump B unable to switch off, which links this code to P27A6. Audi's pump B is the V553 on its 0CJ, 0CK and 0CL gearboxes. Repair centres on the harness; the pump itself is seldom at fault.
P27A5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P27A5
- Stop-start switched off
- Pump B may run continuously or not at all
- MIL after two trips on Type B systems
Common causes of P27A5
- Most likelyControl wire chafed against a powered conductor
- PossibleMoisture bridging the control pin to a supply pin
- Less likelyFaulty output stage in the controlling module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Aux trans pump bWiring harness
What each part of P27A5 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 7 | Area: transmission. |
| A5 | The exact fault in that area. |
What to do next
- Note P27A5 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 P27A5
What does P27A5 mean?
P27A5 means "Electric/Auxiliary Transmission Fluid Pump B Control Circuit High". P27A5 sets when the control line of auxiliary pump B sits at a level that only a connection to a voltage source can explain. It is a generic code, so it means the same on every make.
Is it safe to drive with P27A5?
Drive gently and only to a workshop. With P27A5 the car can go into limp mode (reduced power) to protect itself.
Will P27A5 fail an emissions test?
Yes, it can. P27A5 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 P27A5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P27A5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.