Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 334 (CHARGING SYSTEM - GENERATORS & REGULATORS)DIAGNOSTIC TESTSDTC P0072: AMBIENT TEMP SENSOR LOWTESTING
2004 Toyota Matrix XR, FWD, Standard
DTC P0072: Ambient Temp Sensor Low: Testing
2004 Toyota Matrix XR, FWD, StandardSECTION Testing
WARNING: This page is about a different car, the 2004 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition on, engine not running. With the DRBIII(R), read the Ambient Air Temperature Sensor voltage. If the voltage is below 0.3 volt, go to next step. If the voltage is not below 0.3 volt, go to INTERMITTENT CONDITIONS . Perform POWERTRAIN VERIFICATION TEST VER-5 (NGC) .
- Turn the ignition off. Disconnect the Ambient Air Temperature Sensor harness connector. Turn the ignition on, engine not running. With the DRBIII(R), read Ambient Air Temperature Sensor voltage. If the voltage is above 1.0 volt, replace the Ambient Air Temperature Sensor. Perform POWERTRAIN VERIFICATION TEST VER-5 (NGC) . If the voltage is not above 1.0 volt, go to next step.
- Turn the ignition off. Disconnect the Ambient Air Temperature Sensor harness connector. Disconnect the PCM harness connector. Measure the resistance between ground and the (K25) AAT Signal circuit in the Ambient Air Temperature Sensor harness connector. If the resistance is below 100 ohms, repair the short to ground in the (K145) AAT Signal circuit. Perform POWERTRAIN VERIFICATION TEST VER-5 (NGC) . If the resistance is not below 100 ohms, go to next step.
- Turn the ignition off. Disconnect the Ambient Air Temperature Sensor harness connector. Disconnect the PCM harness connector. Measure the resistance between the (K25) AAT Signal circuit and the (K4) Sensor ground circuit in the Ambient Air Temperature Sensor harness connector. If the resistance is below 100 ohms, repair the (K4) Sensor ground shorted to the (K25) AAT Signal circuit. Perform POWERTRAIN VERIFICATION TEST VER-5 (NGC) . If the resistance is not below 100 ohms, go to next step.
- If there are no possible causes remaining, replace and program the Powertrain Control Module. See PROGRAMMING . Perform POWERTRAIN VERIFICATION TEST VER-5 (NGC) .
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.