P215B: Vehicle Speed - Output Shaft Speed Correlation

What does P215B mean?

P215B checks whether the vehicle speed, as the control unit has chosen it, matches the speed implied by the transmission output shaft. GM uses it widely in hybrids and EVs. The 2011 Volt tables set it, Type A with MIL after one trip, when wheel-based and output-shaft-based speed differ by more than 6.21 mph or when no secured speed source remains, counted over 400 of 800 samples of 25 ms. In the 2019 hybrid tables three sources are compared, output shaft, wheel sensors and motor speeds, and the code sets after 0.15 s when two of them disagree by more than 12.42 mph. GM bulletin 22-NA-089 links P215B on the 2017–2019 Bolt EV to a broken drive shaft washer damaging the wheel speed sensor, which is to be replaced. FCA lists P215B for the Pacifica Hybrid and fixes it with hybrid controller software.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on after one trip
• ABS, traction or stability lamps, systems switched off for the drive
• Clicking noise from a front wheel (Bolt EV)

Common causes

• High Damaged wheel speed sensor (GM Bolt EV broken anti-click washer)
• Medium Faulty transmission output speed sensor or its wiring
• Medium Hybrid or transmission control software (FCA Pacifica Hybrid)
• Low Lost speed message from another module on the data bus

Likelihood is a general estimate across vehicles; your make and model may differ.