B1315

DTC B1315 Evaporator Inlet Temp Sensor Short CKT






Circuit Description

The evaporator inlet temperature sensor is a thermistor that controls the signal voltage to the heater and A/C programmer. The heater and A/C programmer supplies voltage on CKT 731. When the sensor is cold, the following conditions exist:

- The resistance is high.
- The heater and A/C programmer receives a high signal voltage at pin D15.

When the sensor warms, the following actions occur:

- The resistance decreases.
- The signal voltage is pulled low through CKT 407.

The signal voltage varies between 5 V (open circuit) and 0 V (short circuit).

Conditions for Running the DTC

Turn the ignition to the ON position.

Action Taken When the DTC Sets

- The A/C compressor clutch is not allowed to engage.
- The IPC displays SERVICE A/C SYSTEM -- A/C COMPRESSOR OFF.
- A default temperature reading of 5°C (41°F) is implemented.

Notes on Intermittence

If an intermittent DTC B1315 is set, use a Scan Tool in order to select the following settings:

- Data list
- Open/shorts data
- Observe the reading

Manipulate the wiring while observing the Scan Tool . If a failure is induced, the reading will jump. Inspect for the following conditions:

- Poor terminal contact.
- An obstructed or defective sensor.

Test Description

1. Perform the Diagnostic System Check before continuing with the diagnosis of this DTC.
2. The Scan Tool displays the low side temperature. Jumping the harness connector determines if the wiring or the sensor is the cause.