Diagnostic article Generic OBD-II
P0A02: Low circuit indication corresponds to an implausibly hot coolant reading
Read the GM P0A02 electronics-coolant sensor monitor and distinguish circuit-low from physically low temperature.
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Documented application
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
In this GM electronics-coolant sensor circuit, P0A02 is the low-circuit indication. The table represents it as sensor resistance below 25Ω, corresponding to an indicated temperature of at least 162°C. Thus “low” refers to the electrical behavior, not to cold coolant.
Supporting conditions narrow the test
The row requires no active intake-air circuit-low or circuit-high codes. It also specifies a minimum intake-air temperature below 70°C and propulsion-active time greater than ten seconds. The failure decision is 30 failing samples within 50, sampled every 100ms.
Those conditions distinguish this monitor from simply observing a hot value on a scanner. Preserve the electronics-coolant reading together with intake-air validity and the propulsion timeline to see whether the documented comparison was eligible.
A resistance threshold is not a probing instruction
The printed resistance is a calibration description, not a direction to measure an energized circuit or disconnect a sensor beside live high-voltage equipment. The correct vehicle procedure determines whether and where a safe measurement is permitted.
P0A03 is the opposite electrical extreme on the same page, while P0A01 checks temperature plausibility after a soak. Keeping those categories separate helps avoid declaring an overheating event solely from an implausible sensor signal. The document does not identify a particular failed sensor, harness location or repair; those require circuit-specific diagnosis by a qualified technician.
Source and applicability
GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established. GM PDF, page 92.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Motor Electronics Coolant Temperature Sensor A Circuit Low
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT