PCM turns on MIL and uses IAT sensor value instead of ECT sensor value for all calculations during first 5 minutes of operation. After 5 minutes, PCM uses a value of 194°F (90°C). Transaxle shift adapts are maintained at current levels.

NOTE: Test numbers refer to numbers on diagnostic chart.

If sensor or wiring is open, parameter PD04 should indicate -29°C or less.
This checks for open sensor signal in circuit No. 410 from PCM to sensor connector. If parameter PD04 indicates 135-151°C with connector shorted, circuits No. 410 and 808 are okay.
Checks for open in circuit No. 808 from sensor terminal "A" to ground splice. If shorting terminal "A" to ground causes parameter PD04 to indicate 135-151°C, an open in circuit No. 808 exists.
This checks if PCM can recognize a short to ground or low voltage on terminal 1B5, coolant temperature signal. If grounding terminal 1B5 causes PD04 to indicate 135-151°C, circuit No. 410 from PCM to ECT sensor is open.

Fig 1: Code P015 Schematic, Open ECT Sensor Signal

Courtesy of GENERAL MOTORS CORP

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.

Safety Warning

Code P015, Open ECT Sensor Signal: Action

Use the Manual With the Right Hardware

When to See a Mechanic

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