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U0302 Software Incompatibility With Transmission Control Module

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U0302 points to a software or calibration conflict between the transmission controller and its partners. Volkswagen's 2014 Touareg and CC emission specification books show a typical trigger: the engine controller sets U0302 when it is coded for the wrong gearbox type, for instance it receives automatic transmission frames while coded for a manual, or is coded automatic in a manual car. CARB 1968.2 names this very design, a control unit holding manual and automatic variants that lights the MIL when the wrong one is active. GM's 2011 Saab 9-5 treats U0302 as a configuration fault checked at 9-16 V without wiring tests, and the Volkswagen tip 01-18-10TT names it among codes after an engine controller swap. U0101 stands for lost contact, U0402 for invalid data. Expect a MIL and possibly gearbox limp mode.

Likely causes

Engine controller coded for the wrong transmission type
TCM or ECM replaced or updated without matching the partner
Programming of the TCM aborted

Symptoms

  • Check engine light on
  • Harsh or missing shifts, transmission in limp mode
  • Code appears after engine or transmission controller work

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–700
Time0.5–2 h

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

Parts involved

tcmcontrol module software

Related codes

U0101U0402U0301U0304

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