Holden Colorado / Colorado 7 / Trailblazer (RG series, 2014–2020)

• 12721349 (The official GM superseding part number)
• 55591599 (Frequently fitted assembly variant)
• 12633238 (An earlier factory hardware iteration)
• 12721348 (Another verified global E98 equivalent number)
– HW: 55595656
– SW: 55491998, 55491997

• Water Ingress: Moisture breaches the outer physical housing seal, leading to internal circuit board corrosion and an unresolvable U0100 (Lost Communication with ECM) fault code.
• Thermal Solder Stress: Engine bay thermal cycling combined with high-amplitude diesel engine vibration causes micro-cracking in the circuit board's solder joints, manifesting as intermittent engine stalling.
• Internal Processor Corruption: Internal EEPROM/flash memory degradation triggers permanent hardware faults, specifically diagnostic trouble codes P0601, P0602, and P0606 (Internal Control Module Performance).
• 5V Reference Circuit Failure: Physical component degradation inside the module causes a drop in the regulated 5-volt power supply loops to external engine sensors, throwing P0641 or P0651 faults and triggering immediate engine limp-home mode.