Powertrain, generic (extended)

P26A6 Engine Coolant Bypass Valve A Position Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P26A6 means the valve A feedback voltage has dropped below its plausible floor, typically from a short to ground, a lost reference voltage or a failed sensor. GM sets it on the Volt (2011 HPC2/VICM and 2016 VICM) once the signal falls under 5 % of reference, about 0.25 V, in 40 of 50 samples at 100 ms; it is Type B, so the lamp comes on after two trips. Subaru issued a service manual correction for P26A6 (09-132-25: Forester from 2019, Outback/Legacy from 2020, Impreza/Crosstrek from 2021) telling technicians to skip the first diagnostic step. On 2022–2023 Ram 1500 trucks with the 3.6 L V6, bulletin 07-005-24 links P26A6 to a cracked gear and swaps the three-way coolant valve, a job of about 0.7 h.

Likely causes

Feedback wire chafed through and shorted to ground
Open 5 V reference supply to the sensor
Internal sensor failure, e.g. after coolant intrusion
Cracked valve gear (Ram 3.6 L, 07-005-24)

Symptoms

  • Check engine light
  • Delayed warm-up or reduced heater output
  • Valve position shown at or near zero on the scan tool

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

coolant bypass valve aposition sensorwiring harness

Related codes

P26A7P26A4P26A5P26A8P2681P26A3

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.