P2DD1

Code

Generic P — Powertrain

Control Pilot Charging Switch B Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 43 RU: 27

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Page language: EN

Causes

Damaged or corroded connector at the charging inlet or charging control module
Short to battery or other high-voltage/ignition feed on the Switch B conductor
Open or intermittent wiring that allows a pull‑up to a high voltage
Faulty charging control module or CP switch driver transistor
Faulty EVSE (external charging station) or mating connector providing incorrect voltage

Symptoms

Charging may be disabled or intermittent
Charging error message or lamp displayed on dash or infotainment
Vehicle fails to start charging when connected to EVSE
Fault stored in charging system/BCM/ECU

What to check

Read freeze frame and manufacturer-specific charging module data; confirm P2DD1 is current or historic
Visually inspect charging inlet, plug, and harness for damage, corrosion, water ingress or foreign material
Inspect connector pins for bending, corrosion or pushed-out terminals at charging inlet and charging control module
Check related fuses and relays for the charging system
Measure voltage at the Switch B terminal with respect to vehicle ground while connector is connected and while EVSE is plugged/unplugged
Wiggle test harness while monitoring voltage or DTCs to identify intermittent faults

Signal parameters

Expected idle voltage: near 0 V to vehicle reference when driver transistor pulls circuit low (manufacturer-specific)
High/invalid condition: voltage above expected maximum threshold reported by control module (varies by vehicle)
PWM/CP signal characteristics (on vehicles using PWM): duty cycles and frequency expected only when EVSE connected (refer to service data)

Diagnostic algorithm

Safety: Follow HV/EV service safety procedures. Disable high-voltage system if required and wear appropriate PPE before servicing high-voltage components.
Retrieve freeze frame and live data from charging control module/ECU. Note CP Switch B voltage and related status bits with and without EVSE connected.
Visually inspect charging inlet, mating plug, and both ends of the Switch B harness for damage, corrosion or water. Repair as needed.
With vehicle ignition and charging system in the state required by manufacturer, measure DC voltage at the Switch B terminal to ground. Compare to expected values in service data.
If voltage is higher than expected, unplug the connector at the charging control module and measure voltage on the harness pin to locate short to battery/ignition. Check for continuity between the wire and battery positive if it measures high.
Perform a backprobe or disconnect test: disconnect the charging inlet/EVSE and measure whether voltage changes. Test wiring continuity and insulation resistance to chassis ground and to battery positive.
Inspect/replace fuses, relays, or any in-line resistors/pull-ups in the CP circuit if applicable.
If wiring and connectors are good, test or replace the charging control module or its driver transistor. Re-test with a known-good EVSE and clear codes.
After repair, erase DTCs and perform a charging cycle to confirm repair. Document intermittent symptoms and re-check DTCs after several cycles.

Likely causes

Corroded/loose pin at charging inlet or module connector
Wire chafed and contacting battery/ignition feed
Internal failure in charging control module switching transistor or driver
Aftermarket charging equipment or adapter injecting voltage onto CP circuit

Fault status

⚠️ Status

Control Pilot (Charging) Switch B circuit voltage above allowed threshold. Charging control module has detected a high-voltage condition on CP Switch B; charging may be inhibited.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours