What it means
HVIL loop P timing/pattern does not match expected behavior. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
The HVIL confirms that high-voltage connectors and covers are engaged. The module monitors the timing and pattern of loop P's signal; this code sets when the pattern is inconsistent with the expected response, often because of intermittent contact or signal disruption.
Common causes
Most likely first.
- Intermittent contact in HV connector
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Record freeze-frame data and scan all modules for loop P, gateway, and CAN faults to check whether the event occurred with a wider communication interruption.
- Review live loop P status over time, if available, and look for momentary dropouts or unexpected changes.
- With the high-voltage system safely disabled according to the manufacturer's procedure, inspect accessible loop P connectors and harness routing for looseness, rubbing, or damage.
- Have a qualified technician test loop P continuity and signal pattern against the manufacturer's specification, following the permitted harness checks.
- If loop P tests consistently, investigate gateway routing and CAN termination only when network codes or measurements support that direction.
Common fixes
- Secure or replace a loose or damaged loop P connector.
- Repair intermittent or chafed wiring in the loop P circuit.
- Correct gateway routing if testing identifies a communication path fault.
- Repair CAN termination only when testing finds it outside specification.
Can I keep driving?
Do not rely on the vehicle for continued travel if a high-voltage warning, limp mode, or shutdown occurs; an intermittent loop P signal can interrupt high-voltage operation. Keep away from high-voltage wiring and arrange diagnosis promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.