This code indicates that communication bus E on the vehicle's network is detecting a voltage that is stuck high when it should be toggling between high and low states during normal data transmission. It means one or more modules on that bus cannot exchange data properly, which can disable or degrade systems that depend on that bus.
A chafed or damaged wire on the bus E circuit shorted to a power source will hold the line high and prevent normal communication. This is the most common root cause.
Poor terminal contact at a junction connector or module connector can cause an open or high-resistance condition that prevents the bus from pulling low.
A control module on bus E that has internally failed can hold the line at a high voltage level, disrupting communication for all modules on that bus.
A poor ground connection on a module or junction can shift the reference voltage, causing the bus to read abnormally high.
Rarely, the engine computer's internal communication transceiver may fail and hold the bus high. This should only be considered after all wiring, connectors, and other modules on the bus are verified as good.
It depends on which systems are affected by bus E. If safety-related systems such as braking, steering, or stability control are compromised, the vehicle should not be driven until repaired.
No, this is usually incorrect. U0068 is most often caused by wiring, connector, or ground issues, or by another module on the bus failing. The PCM is rarely the root cause and should only be replaced after all other possibilities are fully ruled out.
It means the bus voltage is stuck at a high level rather than switching between high and low as it normally does during data transmission. This prevents modules from communicating.
The standard approach is to disconnect modules on bus E one at a time while monitoring the bus. When the bus returns to normal voltage after disconnecting a specific module, that module is the likely culprit.