U013C: Lost Communication With Accelerator Pedal Module

What it means

ECU lost CAN communication with the accelerator pedal module. Throttle response severely affected. 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
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

The accelerator pedal module reports pedal demand to the vehicle's control system over the data network. U013C sets when expected messages from that module are lost, so throttle response may be restricted and the vehicle may enter a reduced-power mode.

Common causes

Most likely first.

1. Module unpowered
2. Gateway module routing CAN messages incorrectly
3. 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

1. If throttle response is reduced or unpredictable, stop somewhere safe; then scan all modules and save freeze-frame data and communication codes before clearing anything.
2. Check battery voltage and charging-system condition, since low voltage can disrupt module communication and create multiple network faults.
3. Inspect the accelerator pedal module connector and harness for loose pins, moisture, corrosion, or damage, and check for signs of interference around the pedal.
4. Use the wiring diagram to check the module's power, ground, and network connections against the manufacturer's specification.
5. Test the network wiring and gateway routing for opens, shorts, or connection faults using the manufacturer's diagnostic procedure.
6. If the connections are sound, verify whether the accelerator pedal module communicates with a capable scan tool before considering module replacement or configuration.

Common fixes

• Restore battery or charging-system performance if voltage is low.
• Reconnect or repair the accelerator pedal module connector or damaged harness.
• Repair an open, short, or poor connection in the module's network wiring.
• Repair the module's power or ground supply.
• Replace and configure the accelerator pedal module only if it remains unresponsive with sound circuits.

Can I keep driving?

If throttle response is delayed, limited, or unpredictable, do not continue in traffic; pull over safely and arrange assistance. Reduced power or a stalled vehicle can create a hazard, and the fault may leave the accelerator response unreliable.