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U1821

Code meaning and manufacturer information

OBD-II / DTC

Reference meaning

What does this code mean?

The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.

A code identifies a detected condition, not a part that must automatically be replaced.

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A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

Before replacing a part

Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.

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Manufacturer communications

1

Original wording in English

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G-203256 ↗

CADILLAC, CHEVROLET, GMC

14262 - SPECIAL COVERAGE. ON SOME HYBRID 2-MODE (HP2) VEHICLES, THE ACCESSORY POWER MODULE (APM) MAY NOT INITIALIZE WHEN THE VEHICLE IS STARTED IN COLD TEMPERATURES AND THE APM IS COLD. ONCE THE APM WARMS UP, IT WILL INITIALIZE AND PERFORM AS DESIGNED. HOWEVER, DURING THE TIME THAT THE APM IS NOT OPERATIONAL, IT COULD RESULT IN …

Check vehicle applicability

27

A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

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MakeModelModel year
CadillacESCALADE ↗2013
CadillacESCALADE ↗2012
CadillacESCALADE ↗2011
CadillacESCALADE ↗2010
CadillacESCALADE ↗2009
ChevroletSILVERADO 1500 ↗2013
ChevroletSILVERADO 1500 ↗2012
ChevroletSILVERADO 1500 ↗2011

Can I keep driving?

A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.