A010

Diagnostic Chart:

CIRCUIT DESCRIPTION
The outside air temperature sensor is a thermistor that controls the signal voltage to the ACP The ACP applies a voltage on CKT 735 to the sensor. When the sensor is cold its resistance is high, therefore the ACP will see a high signal voltage at pin "D8." As the sensor warms, its resistance becomes less and the signal voltage is pulled low through the sensor ground, CKT 407. This signal voltage will vary between 5V (open circuit) and 0V (short circuit).

TEST CONDITION(S)
1. Ignition "ON."

FAILURE CONDITION(S)
The signal voltages indicates less than -39°C (open circuit) or equal to 53°C (short circuit).

ACTION TAKEN
1. Display "--" on the IPC temperature display.
2. A substitute temperature reading will be implemented to allow operation of the climate control system (AD26 will display the actual sensor reading).

NOTES ON FAULT TREE
1. ACP data value AD26 displays outside temperature. The valid operating range is from -38°C to +52°C.
2. A reading too low indicates an open circuit. Jumpering the harness connector will determine whether the wiring or sensor is the cause of the open.
3. A reading too hi indicates a short circuit. Removing the sensor will determine whether the wiring or sensor is the cause of the short.
4. The open has been determined to be in the wiring. Proviing a ground at the jumper will determine if the open is in the ground wiring or the sensing wire.
5. Grounding the connector at the ACP will determine if the open is in the sense circuit or at the ACP connection/ACP internal.
6. Grounding the connector at the ACP will determine if the open is in the ground circuit or at the ACP connection/ACP internal.

Note values of AD25, AD26, AD27, and AD28. If all read near -40 repair open CKT 407 between ACP and C201 "D." IAD25 and AD26 read near -40 repair open CKT 407 between C201 "D" and S241. If only AD26 reads near -40 repair open CKT 407 between S241 and OAT.

NOTES ON INTERMITTENTS
If the ambient temperature drops below approximately 380°C, this code should be ignored.

If an intermittent Code A010 is being set, select ACP Snapshot Data for Code A010 and note value of AD26. A reaing of approx -40 indicates an intermittent open, a reading of 53 indicates an intermittent short.

Manipulate the related wiring while observing ACP data AD26. If the failure is induce ,the reading will jump outside its normal range.

If the value displayed by AD26 is not reasonably close to the actual temperature of the air at the sensor, check for poor terminal contact, obstructed sensor, or defective sensor.