Powertrain, generic (extended)

P2602 Coolant Pump A Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2602 reports that the control circuit of electric coolant pump A reads low - typically a ground short, or a matching fault report from the driver stage. Which pump is A varies: Ford's 2020-2023 gasoline OBD summary defines it as the auxiliary pump of the high-temperature loop for cabin heating, checked continuously over 5 s above 11 V; GM's 2008 3.6 L LLT table uses an after-run pump (P2602 = circuit to ground, stored only as pending code without warning light). VW's 2014 books set it below about 3.0 V on the Passat and CC and below 2.8-3.2 V on the Touareg. P2600 is the open circuit, P2601 the performance fault, P2603 the high-side fault. Without the pump, heater output or after-run cooling of a hot engine may suffer.

Likely causes

Control wire shorted to ground
Internal fault in the electric coolant pump or its electronics
Coolant or water ingress into the pump connector

Symptoms

  • Fault code stored; MIL depends on the maker (GM 2008 LLT table none, GM 2023 ECM table Type B)
  • Weak cabin heating
  • No after-run of the pump after a hot shutdown

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–500
Time0.5–2.5 h

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

Parts involved

coolant pump aactuator wiringecm

Related codes

P2600P2601P2603

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