Signal Too Low

SPECIAL TOOLS
Volvo scan tool No. 998 8686, or equivalent

SIGNAL TOO LOW
1. Status message

NOTE: To get the correct status message carry out the following before reading the Diagnostic Trouble Code (DTC):

- Preparation:
Ignition ON.
Wait approx. 30 seconds.
Read off the status of the diagnostic trouble code (DTC).
- Is the status permanent?
YES: Proceed to step 2
NO: Proceed to step 9





2. Checking oil temperature sensor signal cable
- Preparation:
Ignition OFF.
Remove the Air Cleaner (ACL) housing to access the transmission connector.
Disconnect the transmission connector.
- Connect an ohmmeter between the transmission connector terminal 12 (transmission side) and the transmission housing.
- Does the ohmmeter read infinite resistance?
- If reading is OK:
Proceed to step 4
- If reading is incorrect:
Proceed to step 3





3. Checking for a short-circuit
- Preparation:
Ignition OFF.
Disconnect transmission connector.
- Check cable between oil temperature sensor and transmission connector terminal 12 for a short-circuit to ground according to step 3 of checking for permanent faults. Checking For Permanent Faults
- If the cable is OK:
Try a new oil temperature sensor, refer to replacement. Service and Repair
Then continue with step 7





4. Checking oil temperature sensor resistance
- Preparation:
Ignition off.
Disconnect transmission connector.
- Connect an ohmmeter between the transmission connector terminals 12 and 13 (transmission side).
- Compare the temperature below with the transmission temperature at the oil temperature sensor.

Specification Table
Temperature: O°C
Resistance (Ohms): 1700-2300
Temperature: 20°C
Resistance (Ohms): 765-1035
Temperature: 40°C
Resistance (Ohms): 340-460
Temperature: 80°C
Resistance (Ohms): 107-143
Temperature: 100°C
Resistance (Ohms): 64-86
Temperature: 150°C
Resistance (Ohms): 23-31

- Does the ohmmeter read approx. 765-1035 Ohms at +20°C (see table)?
YES: Proceed to step 5
NO: Proceed to step 6





5. Checking cable
- Preparation:
Ignition OFF.
Disconnect transmission connector.
- Check cable between transmission connector terminal 12 and Transmission Control Module (TCM) #A14 for a short-circuit to ground according to step 4 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 7





6. Replacing component
- Preparation:
Ignition OFF.
Disconnect transmission connector.
- Try a new oil temperature sensor, refer to replacement. Service and Repair
- Then continue with step 7





7. Verification

NOTE: After repairs have been completed they must be verified as follows to ensure that the fault has been eliminated:
- Preparation:
Ignition OFF
Reconnect the connectors, reinstall components etc.
Ignition ON
Wait approx. 30 seconds.
Read off the DTC status.
- Is the status intermittent?
YES: Fault corrected
NO: Proceed to step 8
8. Fault-tracing information
- The verification result shows that the fault persists.
- Do you want to exit fault-tracing?
YES: Fault not corrected
NO: Proceed to step 1





9. Intermittent fault
- Check the cable between the oil temperature sensor and TCM #A14 for an intermittent short-circuit to ground according to step 3 of checking for intermittent faults. Checking For Intermittent Faults
- Then continue with step 10
10. Fault-tracing information
- For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.
- Do you want to repeat fault-tracing?
YES: Proceed to step 1
NO: Operation done