E015

ECM Code E015:

DFI Sensor Circuit:

DESCRIPTION:

The coolant sensor is a thermistor or variable resistor. The coolant sensor is a two wire sensor with a reference voltage coming from the ECM to sensor pin B on CKT 41OPC and reference ground CKT 476PC connecting sensor pin A to the ECM sensor ground. As the temperature of the sensor decreases, sensor resistance is higher. The signal voltage from the ECM to sensor pin B increases as sensor temperature decreases and less current flows through the sensor element to pin A, sensor ground.

Code E015 "Open Coolant Sensor" sets because the ECM assumes that coolant temperature can't be -35°C or less when the MAT is 5°C or greater; sensor signal is open to sensor.

TEST CONDITIONS:

1. Code E037 and E038 clear.
2. MAT Sensor value greater than or equal to 5°C.

FAILURE CONDITIONS:

Coolant Sensor Value less than or equal to -35°C. (Sensor Signal Open).

ACTION TAKEN:

1. ECM turns on "SERVICE ENGINE SOON" telltale.
2. ECM commands BCM to display "SERVICE SOON" message on CCDIC.
3. ECM turns off both AIR solenoids
4. ECM uses MAT sensor value in place of coolant for all calculations.

NOTES ON FAULT TREE:

1. If sensor is open, parameter ED04 should read -35°C or less. If not then sensor signal is not open, see NOTE ON INTERMITTENTS.

2. Checking for open sensor signal CKT 410 from the ECM to sensor connector. If parameter ED04 reads 148° to 151°C with connector shorted then CKT 410 is OK.

3. Checking for an open sensor ground CKT 476 from the ECM to sensor. If pin "B" to ground causes ED04 to read 148° to 151°C then there is an open in CKT 476 between sensor pin A and ECM terminal D13.

4. Checking for the ECM's ability to recognize a short to ground or low voltage on B8, coolant sensor input.

5. Fault is most likely at the ECM connector or the ECM. Before replacing the ECM, perform "ECM Replacement Check", Chart C-1. Manipulate CKT 41OPC and 476PC wiring, the coolant sensor and ECM connector, while observing ECM parameter ED04. If the failure is induced, the coolant temperature will jump from its normal value to the open circuit reading of -35°C or less. Disconnect and reconnect both the coolant sensor and ECM connectoins and ensure that they are latched before replacing components. If wiring and connectors check out OK, substitute a known good coolant sensor and retest.
Review the snapshot data parameters stored with this code to verify failure condition. If the failure condition is verified, check and repair intermittent wiring connection or sensor.