Powertrain, generic (extended)

P26A5 Engine Coolant Bypass Valve A Position Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Here the feedback signal is electrically present but sits where a healthy valve should never be. In GM's 2016 Volt table the VICM treats readings between 5 and 30 % or between 70 and 95 % of the reference as invalid; 80 failures in 100 samples at 100 ms give a Type B fault, provided the drive codes P2682/P2683/P26AD/P26AE and P26A6/P26A7 are clear. The same GM document lists a faster 3-of-5 variant for the ELR. On the first-generation Volt (2011) this zone check was still part of P26A9. Subaru's bulletin 09-80-21 blames sensor corrosion for P26A-series codes and fits a redesigned valve. A worn sensor track, a damaged gear between motor and sensor or a mis-seated connector are the usual suspects.

Likely causes

Worn or corroded position sensor track inside the valve
Damaged gear or coupling between valve motor and sensor
High contact resistance at the valve connector

Symptoms

  • Check engine light after two drives
  • Engine runs too cool or warms up slowly
  • Fluctuating heater output

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–900
Time0.7–4 h

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

Parts involved

coolant bypass valve aposition sensor

Related codes

P26A4P26A6P26A7P26A9P26A3

References: gsi.ext.gm.com, static.nhtsa.gov, law.cornell.edu.