DTC 142

EAN.Code 1-4-2

1-4-2 Break in oil temperature sensor circuit

DTC information






Conditions for DTC

The oil temperature sensor sends a signal to the TCM which is used for various functions, such as temperature controlled lock-up and initiation of high-temperature programs. The sensor has a temperature sensitive resistance of the NTC (negative temperature coefficient) type. The signal (resistance) sinks proportionate to the rise in the oil temperature. If the TCM receives a signal from the oil temperature sensor the equivalent of a temperature signal below approx. -10°C (12°F)( when the engine is started and the signal has not changed after the engine has been running for approx. 10 minutes, DTC 1-4-2 is set.

Substitution value

No substitution value


Defect cause

- Break in the signal wiring or ground wiring.
- Short circuit to battery voltage in the signal wiring.
- Malfunction in the oil temperature sensor.
- Contact resistance in connections.


Fault symptom

- No fault symptom.
- Fault-tracing starts with EAN1.



EAN1

Checking oil temperature






- Ignition ON.
- Set gearshift selector to position P.

Check whether the transmission oil temperature is reasonable correct by using Diagnostic Test Mode 5. Diagnostic Test Mode 5 Compare with the transmission temperature.

If the oil temperature is reasonable:
- Intermittent fault. Fault-tracing as per EAN8.

If the oil temperature is unreasonable:
- Checking ground wiring EAN2.



EAN2

Checking ground wiring







- Ignition OFF
- Remove the air cleaner (AC) housing to access the transmission connector
- Disconnect the transmission connector.

Connect an ohmmeter between the transmission connector terminal 13 (TCM side) and ground.
The ohmmeter should read approx. 0 Ohms.

If reading is OK
- Checking signal wiring EAN4.

If reading is incorrect:
- Checking the TCM connector EAN3.


EAN3

Checking the TCM connector






- Ignition OFF
- Disconnect transmission connector.
- Check and correct the TCM connector for contact resistance and oxidation as per FA6 FA. Checking Wiring and Connections
- TCM connected

Connect an ohmmeter between the transmission connector terminal 13 (TCM side) and ground.
The ohmmeter should read approx. 0 Ohms.

If reading is OK
- The DTC was set because of poor contact in the TCM connector.

If reading is incorrect:
-Check the cable between the transmission connector terminal 13 and TCM #A15 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections



EAN4

Checking signal wiring






- Ignition OFF
- Disconnect transmission connector.
- Ignition ON.

NOTE: Turning the ignition on when the transmission connector is disconnected can set DTCs for solenoids and the gear-shift position sensor.

Connect a voltmeter between the transmission connector terminal 12 (TCM side) and ground.
The voltmeter should read approx. 5 V.

If reading is OK:
- Checking oil temperature sensor resistance EAN6.

If the voltmeter reads less than 5V:
- Checking the TCM connector EAN5.

If the voltmeter reads more than 5V:
- Check the cable between the transmission connector terminal 12 and the TCM #A14 for short circuit to supply as per FA4. FA. Checking Wiring and Connections

Then continue with: Checking the oil temperature sensor EAN7.



EAN5

Checking the TCM connector






- Ignition OFF
- Disconnect transmission connector.
- Check and correct the TCM connector for contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections
- TCM connected
- Ignition ON.

Connect a voltmeter between the transmission connector terminal 12 (TCM side) and ground.
The voltmeter should read approx. 5 V.

If reading is OK:
- The DTC was set because of poor contact in the TCM connector.

If reading is incorrect:
- Check the cable between the transmission connector terminal 12 and TCM #A14 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections



EAN6

Checking oil temperature sensor resistance






- Ignition OFF
- Disconnect transmission connector.

Connect an ohmmeter between the transmission connector terminals 12 and 13 (transmission side).
The reading should be approx. 765-1035 Ohms at +20°C (68°F) (see table).






If reading is OK:
- The DTC was set because of poor contact in the transmission and TCM connectors. Check and correct the connector for contact resistance and oxidation as per FA6 FA. Checking Wiring and Connections

If reading is incorrect:
- Check the wiring between the oil temperature sensor and transmission connector terminals 12 and 13 for breaks in the circuit as per FA2.
If the wiring is OK: Try a new oil temperature sensor as per Z1-Z12.



EAN7

Checking oil temperature sensor






The oil temperature sensor can malfunction due to a short circuit to supply in the signal wiring. Check the oil temperature sensor as follows:

- Ignition OFF
- Disconnect transmission connector.

Connect an ohmmeter between the transmission connector terminals 12 and 13 (transmission side). The reading should be approx. 765-1035 Ohms at +20°C (680F) (see table).






If reading is OK:
- The oil temperature sensor is OK.

If reading is incorrect:
- Try a new oil temperature sensor as per Z1-Z12.



EAN8

Intermittent Fault.

Checking wiring and connections






- Check the connectors for the transmission and the transmission control module (TCM) for loose connections as per FA5, and contact resistance and oxidation as per FA6. FA. Checking Wiring and Connections

- Check the cable between the oil temperature sensor and TCM #B14 for intermittent break as per FA2 and intermittent short circuit to supply as per FA4.

- Check the cable between the oil temperature sensor and TCM #A15 for intermittent breaks as per FA2. FA. Checking Wiring and Connections