GM P00B7/P2181: cooling-path blockage rather than a guessed thermostat. See the manufacturer document, vehicle conditions, exclusions and questions for a qualified shop before assuming a repair.
This is a research summary of a manufacturer communication, not a diagnosis for your car, a DIY repair procedure or confirmation of warranty or recall eligibility. No qualified technician has approved a repair for your individual vehicle here.
This historical communication is conditional. The current revision, VIN/build eligibility, measured diagnosis and any warranty or recall decision are not established here. Ask the manufacturer or a qualified shop to check the complete current document.
Read the General Motors original: P00B7/P2181, overheating and restricted cooling passages · Check open recalls by VIN at NHTSA Source date: 2015-06; research checked: 2026-11-01.
What prompted this manufacturer document
- Restricted coolant passages can accompany overheating, weak cabin heat or air-conditioning shutdown.
- The source distinguishes an outlet molding/debris condition on 2013 vehicles from other hose/bypass restrictions.
Which vehicle conditions must be checked
Each row below retains its own conditions. Do not combine engines, years or models across rows to create new applications. A listed model is not proof that a particular VIN is affected.
- Buick Regal · 2014, 2015 · Applicable 2.0/2.5L LCV/LKW/LTG; verify actual model engine
- Cadillac ATS · 2013, 2014, 2015 · Applicable LCV/LKW/LTG engine; verify model-specific combination
- Cadillac CTS · 2014, 2015 · Applicable LCV/LKW/LTG engine; verify model-specific combination
- Chevrolet Malibu · 2013, 2014, 2015 · Applicable 2.0/2.5L LCV/LKW/LTG
- Chevrolet Impala · 2014, 2015 · Applicable 2.0/2.5L LCV/LKW/LTG
- The model list and engine/RPO list are not a license to create every model-engine combination.
Codes recorded in this document
A root listed only as an appearance has no separately verified meaning here. Preserve every suffix and module name; a shared root does not transfer a repair branch to another vehicle.
| Root | Raw form | Meaning in this source, if established |
|---|---|---|
| P00B7 | P00B7 | Appears in the document; individual meaning not verified |
| P2181 | P2181 | Appears in the document; individual meaning not verified |
What an owner can record safely
- Record whether cabin heat weakened before the temperature warning.
What the source does not prove
- Never open a hot pressure cap or substitute a thermostat without diagnosis.
- A code or message alone does not establish a failed part, a safe-to-drive decision or an approved repair for this VIN.
- A service bulletin is not automatically a recall or free warranty repair. Confirm current eligibility directly.
Questions for the repair shop
- Was flow restriction checked at the outlet and heater/bypass circuit?
- Does a later revision or a current recall change the source's original advice?
- What measurement or inspection confirms the cause, and how will the repair be verified?
Read the original record
The linked communication may be revised after the research date. Compare its document number, exact vehicle table, diagnostic preconditions and exclusions with a qualified technician. This page paraphrases selected facts and does not reproduce the manufacturer procedure.
Sources and scope
- General Motors — P00B7/P2181, overheating and restricted cooling passages (PIP5300) Document: 2015-06 · Research checked: 2026-11-01
Research snapshot: 2026-11-01. Source documents may have newer revisions. Verify current instructions and VIN eligibility with the manufacturer.