P0867

Code

Generic P — Powertrain

Transmission Fluid Pressure

Brand: Generic

Type: P — Powertrain

Views: UK: 34 EN: 134 RU: 54

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Page language: EN

Causes

Low transmission fluid level
Contaminated, burnt, or degraded transmission fluid
Clogged transmission filter or strainer
Faulty transmission fluid pressure sensor or pressure switch
Damaged wiring harness or poor connector connection to the pressure sensor
Weak or failing transmission oil pump

Symptoms

Check Engine Light and/or Transmission/TC warning lamp
Poor or harsh shifting, slipping, delayed engagement
Transmission stuck in limp/diagnostic mode
Unusual transmission noises (whine or groan) under load
Transmission overheating warning or higher than normal operating temp
Fluid leaks or visible low fluid level

What to check

Read and record all stored and pending codes plus freeze-frame data with a scanner
Check transmission fluid level, color, and smell (burnt odor) with warm engine and correct procedure
Inspect transmission fluid filter/strainer (replace if service interval or contaminated)
Visually inspect sensor connector and harness for corrosion, looseness, or damage
Backprobe pressure sensor and observe live data (voltage or PID) while varying engine load
Measure transmission line/actual hydraulic pressure with a mechanical gauge at the manufacturer test port

Signal parameters

Typical pressure sensor output: 0–5 V (model dependent); voltage should rise with increasing engine load and gearbox pressure
Low-pressure condition: sensor voltage low (often
High-pressure condition: sensor voltage high (often >4.0–4.5 V) when under load; verify against manufacturer data
When using a mechanical gauge: line/apply pressure should meet OEM specifications for park/idle/drive and under load (varies by transmission)
Sensor resistance/continuity: compare to OEM spec; open or short indicates sensor/harness fault

Diagnostic algorithm

Connect a capable scan tool, record DTCs and freeze-frame data. Note operating conditions when the fault set.
Visually inspect transmission fluid level and condition. Top or replace fluid if low/contaminated, then clear codes and retest.
Inspect sensor connector and wiring for damage, corrosion, or loose pins. Repair any damage and clear codes to retest.
Backprobe the pressure sensor output and reference circuits. Verify reference voltage, ground, and sensor signal against OEM values.
Monitor live data PIDs for transmission pressure while varying engine load/gear. Check for expected response (signal should change smoothly with load).
If electrical checks are OK but sensor signal indicates low pressure, connect a mechanical pressure gauge at the service port and compare readings to specifications.
If mechanical pressure is low, investigate pump condition, valve body, clutches, and seals. Perform component-level tests (pump flow/pressure, leak-down) per service manual.
If mechanical pressure is correct but sensor output is incorrect, replace the pressure sensor/switch and retest.
After repairs, clear codes, perform road test under similar conditions that produced the fault, and confirm code does not return.

Likely causes

Low or contaminated fluid discovered on visual check
Intermittent or damaged wiring to pressure sensor (corrosion, chafing)
Pressure sensor returns low voltage or no signal when back-probed
Mechanical loss of line pressure when checked with a pressure gauge
Related transmission codes present (pump/valve body/clutch faults)

Fault status

⚠️ Status

Transmission fluid pressure below expected range or transmission pressure sensor/switch circuit fault detected. Possible causes include low/contaminated fluid, faulty sensor or wiring, clogged filter, weak pump, or internal hydraulic leak. Further diagnosis required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-4.0 hours