P2032

P2032-EXHAUST GAS TEMPERATURE SENSOR CIRCUIT LOW- BANK 1 SENSOR 2





For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The Exhaust Temperature sensors are used by the electronic control module (ECM) to monitor the engine exhaust temperatures in the aftertreatment system. The Exhaust Temperature sensors are thermistors and change resistance based on the temperature being measured. The ECM provides a 5-volt reference voltage to the sensor. The ECM monitors the change in signal voltage and converts this to a temperature value. When the exhaust gas temperature is cold, the sensor or thermistor resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to ground. Therefore, the ECM senses a high signal voltage or low temperature. When the exhaust gas temperature is hot, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature. The ECM will set the fault code if it detects that the aftertreatment diesel particulate filter inlet exhaust gas temperature sensor signal voltage is less than a calibrated voltage for longer than a calibrated period. The ECM illuminates the MIL lamp immediately when the diagnostic runs and fails. A default value for the aftertreatment diesel particulate filter inlet temperature reading will be used and active regeneration of the diesel particulate filter will be disabled. The ECM will turn off the MIL lamp immediately after the diagnostic runs and passes.

- When Monitored:

Ignition ON

- Set Condition:

The ECM will set the fault if it detects that the diesel oxidation catalyst inlet exhaust gas temperature sensor signal voltage is greater than a calibrated voltage for more than a calibrated time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. TEMPERATURE SENSOR

Disconnect the Exhaust Gas Temperature Sensor 1/2.


NOTE: Check connectors - Clean/repair as necessary.

Using an ohmmeter check the resistance of the sensor.


NOTE: The sensor's resistance value increases with decreasing temperature @ 50° C (122° F) resistance ranges from 82k to 137k ohms.

Is the resistance between 82k and 300k ohms at ambient temperature?

Yes

- Go To 2

No

- Replace the sensor
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (K186) EXHAUST TEMPERATURE 1/2 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Reconnect the Temperature sensor.

Disconnect the ECM harness connector.


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the (K186) Exhaust Temperature 1/2 Signal circuit and (K900) Sensor ground circuit at the ECM harness connector.

Is the resistance between 82k and 300k ohms at ambient temperature?

Yes

- Go To5

No

- Go To 3

3. (K186) EXHAUST TEMPERATURE 1/2 SIGNAL CIRCUIT SHORTED TO GROUND

Disconnect the Exhaust Temperature Sensor 1/2.

Measure the resistance between the (K186) Exhaust Temperature 1/2 Signal circuit and ground from the sensor harness connector.

Is the resistance greater than 100 Ohms?

Yes

- Go To 4

No

- Repair the short to ground in the (K186) Exhaust Temperature 1/2 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. (K900) SENSOR GROUND CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (K900) Sensor ground circuit in the sensor harness connector.

Is the resistance greater than 100 Ohms?

Yes

- Go To

No

- Repair the short to ground in the (K900) Sensor ground circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (K186) EXHAUST TEMPERATURE 1/2 SIGNAL CIRCUIT SHORTED TO ANOTHER CIRCUIT

Measure resistance from (K186) Exhaust Temperature 1/2 SIGNAL circuit to all other circuits at the ECM harness connector.

Is the resistance more than 100 k ohms?

Yes

- Go to 6

No

- Repair the short between the circuits.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. ECM

Reconnect the ECM harness connector.

While monitoring the Exhaust Temperature Sensor 1/2 with scan tool, connect and disconnect the Exhaust Temperature Sensor 1/2 harness connector.

Does the voltage go from low with the sensor connected to high with the sensor disconnected?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test