Powertrain, generic (extended)

P2A89 Alternative Fuel Pump C Compression Stroke Valve Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2A89 is set when the drive circuit of pump C's compression stroke valve reads low for the commanded state. Most often the control wire has found a path to ground, so the solenoid may stay on, or the coil has shorted turns and pushes the output stage into current limiting. A valve stuck in fill keeps pressurised oil behind element C; that element stops cycling, and the others have to carry its share. Expect reduced fuel delivery at high load rather than an immediate stall, at least on pumps with several elements like Caterpillar's design. No manufacturer publishes P2A89. Unplug valve C and check whether the short to ground remains in the harness; if it disappears, the coil is the likely culprit.

Likely causes

Control wire of valve C shorted to ground
Shorted turns in the coil of valve C

Symptoms

  • Warning lamp on
  • Reduced power at high load

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,500
Time1–4 h

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

Parts involved

alt fuel pump c compression stroke valvewiring harnessafcm

Related codes

P2A87P2A88P2A8AP2A81P2A85

References: law.cornell.edu, patents.google.com.