The P071B: Transmission Mode Switch ‘A’ Circuit Low refers to a problem where the signal from the transmission mode switch A is too low. This can be due to a faulty switch, wiring issues, or poor electrical connections, which could affect the vehicle’s ability to change transmission modes correctly.
P071B – Quick Overview
| Code | Information |
|---|---|
| Meaning | P071B: Transmission Mode Switch ‘A’ Circuit Low |
| Is it serious? | Yes, as low signal issues can cause the transmission to function incorrectly or prevent mode switching. |
| Possible causes | – Low signal from transmission mode switch A – Faulty switch – Wiring issues |
| How to diagnose? | – Test the switch signal – Inspect wiring and connectors – Replace switch if necessary |
P071B Meaning
The P071B code is triggered when the transmission mode switch A sends a low signal to the transmission control module (TCM). This switch allows the driver to select different transmission modes, and a low signal could prevent the transmission from responding properly to mode changes.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for other transmission-related codes that may offer additional insights into the mode switch issue. | OBD-II Scanner |
| Test the Switch Signal | Use a multimeter or diagnostic tool to test the voltage or signal from transmission mode switch A. Compare the readings with manufacturer specifications to ensure it is not too low. | Multimeter, Diagnostic Tool |
| Inspect Wiring and Connectors | Visually inspect the wiring and connectors associated with the transmission mode switch for signs of damage, corrosion, or loose connections that could cause a low signal. | Flashlight, Multimeter |
| Inspect for Electrical Faults | Check for any electrical faults that may affect the transmission mode switch circuit. Ensure that all fuses related to the circuit are intact. | Fuse Tester, Multimeter |
| Replace the Switch if Necessary | If the switch is producing a low signal, replace it with a new transmission mode switch to restore proper function. | Replacement Parts, Standard Tools |
| Clear Code and Retest | After repairs, clear the code using an OBD-II scanner and take the vehicle for a test drive to ensure the issue is resolved. | OBD-II Scanner |
| Recheck for Codes | After the test drive, re-scan the vehicle to ensure the P071B code has not returned. | 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