Powertrain
generic / SAE
P27A1
Electric/Auxiliary Transmission Fluid Pump A Stuck On
The first auxiliary transmission fluid pump runs even when no command is active.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number7 / A1
Possible causes
- TCM output driver stuck on high
- Control wire shorted to a permanent B+ supply medium
- Carbon or debris buildup preventing free movement low
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 180–1000 €
- Estimated time: 0.8–3.5 h
- Component: aux trans pump a
- Component: control module
- Component: wiring harness
- MIL / check engine light
Sources
References
sae:J2012