P27AB

Code

Generic P — Powertrain

Pressure Control Solenoid E Data Incompatible

Brand: Generic

Type: P — Powertrain

Views: UK: 34 EN: 39 RU: 34

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Page language: EN

Causes

Faulty pressure control solenoid E (stuck, intermittent, internal short)
Damaged wiring harness or poor connector (open, short to ground/power, corroded pins)
Faulty transmission control module (TCM) or powertrain control module (PCM) software/calibration mismatch
Low or degraded transmission fluid causing abnormal solenoid response
Valve body hydraulic/mechanical fault affecting solenoid operation
Intermittent ground or supply voltage problem

Symptoms

Malfunction Indicator Lamp (MIL) or transmission warning light illuminated
Harsh, delayed, or incorrect shifts; transmission may go into limp mode
Unusual transmission noise or shudder during shifts
Reduced drivability or performance
Diagnostic trouble code P27AB stored; may be accompanied by other transmission codes

What to check

Retrieve freeze frame and full code list with a capable scan tool; note conditions when code set
Check for manufacturer Technical Service Bulletins (TSBs) or calibration updates
Visually inspect transmission fluid level and condition (color, odor, contamination)
Inspect wiring harness and connector for solenoid E for damage, corrosion, loose pins, or water ingress
Backprobe connector and check for correct supply voltage and ground with ignition ON
Measure resistance of solenoid E (compare to factory spec or to another identical solenoid if available)

Signal parameters

Typical DC resistance (solenoid coil): approx. 10–50 ohms (varies by vehicle) — compare to factory spec
Control signal: PWM duty cycle controlled by TCM (0–100%); driver switches between battery voltage and ground
Supply voltage at connector with ignition ON: near battery voltage (approx. 9–14 V) when not driven
When commanded, waveform should show pulsed voltage per commanded duty cycle — look for missing pulses, stuck high/low, or excessive noise

Diagnostic algorithm

Read and record all codes, freeze frame and live data. Note if other solenoid or transmission codes are present.
Check TSBs and confirm correct module software/calibration. Reflash/replace software if required before parts replacement.
Inspect transmission fluid level/quality; if very low or contaminated, service fluid and filter, then retest.
Visually inspect solenoid E connector and harness; repair any damage, corrosion, or poor connections.
Measure solenoid resistance with connector disconnected and compare to spec or another solenoid. Replace solenoid if resistance is open/short or significantly out of range.
Backprobe and command solenoid with a scan tool; observe control waveform and supply/ground. If waveform/voltage is incorrect, diagnose wiring or module driver.
Perform continuity and short checks between solenoid connector and TCM connector; repair wiring faults as needed.
If wiring and solenoid test good and software is current, consider TCM fault—verify with manufacturer procedures, swap or reflash module only after exhaustive checks.
Clear codes and perform a road test while monitoring live data; confirm proper operation before closing repair order.

Likely causes

Damaged connector or wiring to solenoid E
Failed solenoid E (electrical or internal mechanical failure)
Contaminated or low transmission fluid affecting solenoid function
TCM/PCM firmware or parameter mismatch after service

Fault status

⚠️ Status

P27AB — Pressure Control Solenoid E: data from the solenoid is incompatible or out of expected range as detected by the control module. Indicates electrical, mechanical, fluid condition, or module/software issues affecting solenoid E.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours