Chassis, generic

C0242 PCM Indicated Traction Control Malfunction

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C0242 is a GM brake module code that the accessible J2012 lists do not contain. The Saab 9-5 and 9-4X of 2011 describe it as Powertrain Control Module Indicated Traction Control Malfunction, and the GM bulletin PIC4740C for the 2007 Cadillac STS calls it ECM Indicated TCS Malfunction. During traction control the brake module asks the engine module over the data bus for less torque. When the engine module holds certain faults of its own, it replies that it cannot cut torque, and the brake module stores C0242. Traction and stability control then stay off for the ignition cycle and their lamp comes on. The real fault sits in the engine or transmission module, so its codes are read first; in PIC4740C a loose transmission connector X1 was the cause.

Likely causes

Stored fault in the engine control module that blocks torque reduction
Loose or poorly seated terminals at the transmission connector (GM PIC4740C)
Faulty engine control module, rarely the brake module

Symptoms

  • Traction or stability control lamp on, systems disabled
  • Check engine lamp or reduced engine power from the engine side fault

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–900
Time0.5–3 h

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

Parts involved

powertrain control moduleabs control modulecommunication bus

Related codes

P0856C061BC0561

References: saabwisonline.com, saabwisonline.com, static.nhtsa.gov.