The P0B39: Motor Electronics Coolant Pump “B” Control Circuit Low code indicates a low voltage condition in the control circuit for coolant pump “B.” This could be caused by faulty wiring, damaged connectors, or a malfunctioning control module. If left unresolved, this issue could affect the cooling system’s performance, leading to overheating of the motor electronics.
P0B39 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0B39: Motor Electronics Coolant Pump “B” Control Circuit Low |
| Is it serious? | Yes, low voltage in the control circuit can prevent proper cooling, potentially leading to motor electronics overheating. |
| Possible causes | – Low voltage in coolant pump B control circuit – Faulty wiring or connectors – Malfunctioning control module |
| How to diagnose? | – Measure voltage in coolant pump B control circuit – Inspect wiring and connectors – Test control module functionality |
P0B39 Meaning
The P0B39 code is triggered when the voltage in the motor electronics coolant pump “B” control circuit is lower than expected. This could be due to wiring issues, loose or damaged connectors, or a problem with the control module. If the coolant pump cannot receive adequate power, it may not function correctly, which could lead to overheating of the motor electronics.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional codes that might provide more insight into the cooling system or electronics. | OBD-II Scanner |
| Measure Voltage in Coolant Pump B Control Circuit | Use a multimeter to measure the voltage in the coolant pump B control circuit and compare it with manufacturer specifications. | Multimeter |
| Inspect Wiring and Connectors | Inspect the wiring and connectors for signs of damage, corrosion, or loose connections that could be causing low voltage in the circuit. | Flashlight, Multimeter, Safety Gloves |
| Test Control Module | Use a diagnostic tool to test the control module for proper functionality. If the module is not providing adequate voltage to the circuit, it may need to be replaced or reprogrammed. | Diagnostic Tool |
| Clear the Code and Test Drive | After repairs, clear the code and take the vehicle for a test drive to verify that the issue is resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | Rescan the vehicle after the test drive to confirm that the P0B39 code does not return. | OBD-II Scanner |
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko