U0087 indicates that the voltage on CAN bus F is higher than expected, usually caused by a short to power, excessive resistance, or a faulty transceiver driving the bus high. This triggers a communication fault that can affect multiple modules sharing the bus.
A chafed harness, pinched wire, or water intrusion can pull the CAN line up to battery voltage, triggering the high‑bus condition.
Corrosion, bent pins, or loose contacts at a module or splice can create a high‑resistance path that reads as a high voltage on the bus.
A defective transceiver IC in a body control module, gateway, or other ECU can drive the bus high even when the wiring is intact.
Missing or changed 120 Ω termination resistors at the ends of the bus can cause reflections that appear as a high‑voltage condition.
While the powertrain control module can theoretically cause a bus‑high fault, it is uncommon; most U0087 cases are resolved by wiring or module repair, not PCM replacement.
No. The PCM is rarely the cause; most U0087 faults are due to wiring shorts, connector issues, or a faulty module transceiver on bus F. Replacing the PCM without first checking the bus wiring often does not resolve the code.
A blown fuse usually results in a loss of communication (low bus) rather than a high‑bus condition, but if the fuse protects a power feed to a transceiver, its loss could lead to erratic voltage; check fuses as part of the inspection.
Driving may be possible if only non‑critical systems are affected, but because the code can indicate a bus fault that may impair safety‑related modules (ABS, stability control, etc.), it is advisable to diagnose and repair the issue promptly.