Signal Too Low
Signal too low
Checking the function
- Ignition on.
Check the sun sensor signal by varying the intensity of the light that it detects. Cover the sun sensor with your hand to obtain the minimum signal, approximately 0.5 volts.
Then aim a strong light source (for example a flashlight) at the sun sensor from close range to increase the signal.
Hint: If the signal from the sun sensor is a steady less than 0.25 volts, there is either a short-circuit to ground in the cable or the sun sensor is defective.
Click on the VCT2000 symbol to read off the sun sensor signal.
Note! The illustration only shows the method. The appearance of the sun sensor can vary between different models.
Does the value change?
Yes - Checking connectors and wiring
No - Checking the connector
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Checking the connector
- Ignition off
- Check the central electronic module (CEM) connector (terminals (#B5 (#5), #B28 (#28)) and the sun sensor connectors. Check for contact resistance. Check for oxidation. Check for damage carefully.
Other information
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Signal specification Signal Description, Central Electronic Module (CEM)
- Location of components Component Location, Central Electronic Module (CEM)
- Sun sensor Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
Was a fault detected?
Yes - Verification
No - Checking the component and wiring
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Checking the component and wiring
Check the signal cable between central electronic module (CEM) terminal #B5 (#5) and sun sensor terminal #3. Check for an open-circuit. Check for a short-circuit to supply voltage.
Check the ground lead between central electronic module (CEM) terminal #B28 (#28) and sun sensor terminal #5. Check for an open-circuit. Check for a short-circuit to supply voltage.
Replace the sun sensor if no fault is found in the wiring.
Remedy as necessary.
Other information
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Signal specification Signal Description, Central Electronic Module (CEM)
- Location of components Component Location, Central Electronic Module (CEM)
- Sun sensor Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
Select "Continue" when the fault has been remedied.
Continue - Verification
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Checking connectors and wiring
Check the central electronic module (CEM) connector (terminals #B28, #B30) and the sun sensor connectors. Check for contact resistance. Check for oxidation. Check for damage carefully.
Check the signal cable between the central electronic module (CEM) terminal #B28 (#28) and sun sensor terminal #TBD (#TBD). Check for a short-circuit to ground.
Check the ground lead between the central electronic module (CEM) terminal #B30 (#30) and sun sensor terminal #TBD (#TBD). Check for a short-circuit to ground.
Other information
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Signal specification Signal Description, Central Electronic Module (CEM)
- Location of components Component Location, Central Electronic Module (CEM)
- Sun sensor Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
Continue - Fault-tracing information
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Check the solar sensor signal by varying the light intensity at the sun sensor. Cover the sun sensor with your hand to reduce the signal. Then aim a strong light source (for example a flashlight) at the sun sensor from close range to obtain the maximum signal.
The value should vary between approximately 0.5 and 4.85 volts.
Is the function OK?
Yes - Troubleshooting procedure complete
No - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit Fault-Tracing
No - Attempt New Test
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Attempt New Test - Checking the function
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Fault-tracing information
Information
Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).
Do you want to view the information again?
Yes - Attempt New Test
No - Exit Fault-Tracing
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Attempt New Test - Checking the function
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