Parts for your 2012 Holden Colorado-Temperature sensors

2012 Holden Colorado temperature sensors

Temperature sensors are definitely used on the 2012 Holden Colorado. Holden/GM Service Information for the RG Colorado (2012MY) and associated wiring diagrams list engine coolant temperature (ECT), intake air temperature (IAT), ambient air temperature, and automatic transmission fluid temperature sensors as monitored inputs. Parts catalogues for the RG Colorado also identify these sensors as service items, confirming their relevance and fitment.

On this model, temperature sensors let the ECU and other control modules make smart decisions. The ECT sensor tells the engine how warm it is, so it can sort cold-start fuelling, idle speed, radiator fan operation, and overheat protection. The IAT reading helps with fuelling and boost control, especially under load or on hot days. The ambient sensor helps the HVAC system behave properly, and the transmission fluid temperature sensor (autos) shapes shift timing and protects the box when things get hot. Some variants and later updates may also use exhaust temperature sensing for emissions control.

They’re generally maintenance-free, but they do benefit from good servicing habits. Keep the cooling system healthy with the correct long-life coolant, fix leaks early, and don’t ignore a wandering temperature gauge or the fan running flat-out all the time. Corrosion, old coolant, or dirty connectors are common causes of dodgy readings.

• Typical symptoms of a failing temp sensor or circuit:
  • Hard cold starts, rich running, or poor fuel economy
  • Erratic temperature gauge or radiator fan always on
  • A/C cutting out, rough shifts on autos, or limp mode
  • Stored fault codes such as P0115–P0119 (ECT), P0110/P0112/P0113 (IAT), P0070–P0074 (ambient)

Replacement is straightforward for most driveway tinkerers. Work on a cold engine. Depressurise and drain enough coolant to drop the level below the ECT sensor. Unplug the connector, remove the sensor, and fit a new one with a fresh seal. Refill and bleed the cooling system, clear any codes, and confirm readings with a scan tool, ECT and IAT should read close to ambient when the engine’s stone-cold. Handle connectors gently and avoid sealants unless specified—most sensors use an O-ring and don’t need thread tape.

There’s no fixed replacement interval—these are “replace on condition” parts. As part of a regular service on a 2012 Colorado, it’s smart to:

• Scan live data to verify plausible ECT/IAT/ambient readings
• Inspect wiring and plugs for oil, coolant wicking, or corrosion
• Renew coolant on schedule to prevent corrosion around the ECT sensor

Keeping these little guardians happy helps the Colorado start cleanly, pull hard, and keep its cool in Aussie and Kiwi conditions.

FAQ

Where is the engine coolant temperature sensor on a 2012 Holden Colorado?
On the 2.8-litre turbo-diesel, the ECT sensor is typically mounted near the thermostat housing at the front/side of the cylinder head, plugged into a coolant passage. Access is usually from the top of the engine once the intake ducting is moved aside.

Some variants place it directly on the housing, others have it in the head close by. If unsure, follow the upper radiator hose to the thermostat area and look for a two-pin sensor.

What fault codes point to a bad temperature sensor?
Common ECT codes are P0115, P0116, P0117, P0118, and P0119. For IAT you’ll often see P0110, P0112, or P0113, and for the ambient sensor P0070–P0074 are typical. A scan tool showing implausible values (for example, –40°C or 140°C) is also a giveaway.

Always check the wiring and connector before condemning the sensor—broken grounds and green, corroded pins are frequent culprits.

Is it safe to drive with a faulty coolant temperature sensor?
Not recommended. The ECU may default to rich fuelling, run the fan constantly, or enter limp mode. More importantly, you could miss an actual overheat because the gauge and warnings rely on accurate temperature data.

If the gauge is erratic or there are codes, sort it promptly to avoid engine or transmission damage.