Powertrain, generic · Computer and auxiliary outputs

P06B6 Internal Control Module Knock/Combustion Vibration Sensor Processor 1 Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

To detect an open knock sensor circuit, GM's engine modules feed a 20 kHz test signal into the sensor circuit and check whether it returns. P06B6 checks the internal test circuit or knock signal processor for sensor 1: it sets when the returned 20 kHz component lies between the open-circuit thresholds, so the module cannot decide 'connected' or 'open'. GM rates it type B (two trips), type A in some 2025 modules; Saab retards ignition timing as a reaction. GM bulletin 22-NA-229 calls for reprogramming only, not part replacement. Ford uses P06B6 for lost communication with its knock chip (more than 200 cylinder events). Knock sensor circuit codes are P0325–P0328.

Likely causes

Engine module software (GM bulletin)
Internal knock processor or test circuit faulty
Knock sensor wiring with high resistance or intermittent contact
Knock sensor faulty

Symptoms

  • Check engine light
  • Retarded ignition, less power and higher consumption
  • Often no other symptoms

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,200
Time0.5–3 h

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

Parts involved

engine control moduleknock sensor

Related codes

P06B7P0325P0327P0328P0324

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, newtonnet.co.uk.