Poor connection, corrosion or damaged wiring in the wake-up signal circuit; Low battery voltage or weak battery causing unstable supply during wake-up; Poor power or earth connections to the control module; Faulty ignition switch, start/stop switch or relay supplying the wake-up signal; Another module or network fault keeping the bus awake or sending a faulty wake-up request; Water ingress or damage at the control module connector; Internal fault in the control module wake-up circuitry.

P06E4

Control Module Wake-up Circuit Performance.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
E4: FaultThe specific fault in that area

What it means

P06E4 means the control module has found a performance problem in its wake-up circuit, the signal path that brings the module out of sleep or low-power mode when the ignition is switched on or another module requests it. The module saw a wake-up signal that was missing, late, unstable or out of its expected range or timing. The exact wake-up source and the logic used to set the code vary by model and engine, so check the manufacturer wiring diagram.

Symptoms

Engine cranks but is slow to start or does not start
Warning lights on the dashboard, including the engine management light
Intermittent loss of communication with the control module
Battery drain overnight or modules staying awake
Other stored communication or low-voltage fault codes
Erratic or intermittent starting that comes and goes

Possible causes

Poor connection, corrosion or damaged wiring in the wake-up signal circuitlikely
Low battery voltage or weak battery causing unstable supply during wake-uplikely
Poor power or earth connections to the control modulelikely
Faulty ignition switch, start/stop switch or relay supplying the wake-up signalpossible
Another module or network fault keeping the bus awake or sending a faulty wake-up requestpossible
Water ingress or damage at the control module connectorpossible
Internal fault in the control module wake-up circuitryrare

How to diagnose

Read all stored codes and freeze frame data, noting battery voltage and conditions when the code set, and look for related network or voltage codes
Test battery condition and charging system output, and check the terminals are clean and tight
Visually inspect the module connector, wiring and fuses and relays in the wake-up circuit for corrosion, chafing, moisture or loose pins
Check the module power supplies and earths with a multimeter for voltage drop under load
Using the wiring diagram for the vehicle, test the wake-up signal for presence, voltage and continuity at the module while operating the ignition or start switch
Check the ignition switch, start button or relay that provides the wake-up signal
Use a scan tool to check which other modules are online and look for a module keeping the network awake
Check for software updates or technical service bulletins for the specific model before considering module replacement

How to fix

Charge or replace a weak battery and clean and tighten the terminals
Repair or replace damaged wiring, connectors or terminals in the wake-up circuit
Restore good power and earth connections to the control module
Replace a faulty ignition switch, start switch or relay
Repair or replace any other module or network component found to be causing the wake-up fault
Replace or reprogramme the control module only after wiring and supply faults are ruled out, or where an outdated calibration is a known cause

Can I keep driving?

Medium severity

The car may be driven short-term if it starts and runs normally, but get it checked soon as it could fail to start or lose module communication unexpectedly. If it is starting poorly or showing other warnings, avoid longer journeys.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.