P2D73

Code

Generic P — Powertrain

Battery Charging System Negative Contactor D Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 20 EN: 37 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or shorted wiring between control module and contactor coil/driver
Disconnected, corroded or damaged connector at the contactor or ECU
Failed contactor coil or contactor mechanical failure
Failed driver transistor or output stage in the charging/BCM/ECU
Blown fuse or tripped protection device in the contactor supply/driver circuit
High-voltage interlock or safety relay preventing contactor operation

Symptoms

Charging disabled or intermittent charging of HV battery
EV/Hybrid may show charging-system or battery warnings on dash
Vehicle may refuse to start/enter ready state or will limp to a reduced state
High-voltage system fault lamp or general warning lamp illuminated
Possible loss of power feed to charging circuits or inability to close contactor

What to check

Observe and record freeze-frame and live-data from scan tool; confirm DTC and status of contactor command and feedback
Perform visual inspection of wiring, connectors and contactor for damage, corrosion, water intrusion
Ensure vehicle is made safe for HV work per manufacturer procedure before touching components
Check fuses, service disconnects and protection devices related to charging/contactors
Verify connector pin retention and wiring continuity from module to contactor with power removed
Measure voltage at the contactor control connector while commanding the contactor (use proper HV/12V precautions)

Signal parameters

Control type: switched coil driver (low-side or high-side) controlled by charging/BCM/ECU
Command signal: battery or system control voltage when ON (12 V in auxiliary control or HV pilot depending on design); 0 V when OFF
Feedback: some systems provide closed-loop status or current sensing instead of direct feedback
Coil resistance: typically low-ohm value (vehicle-specific). Expect measurable continuity (not infinite).
Current draw when energized: typically small to moderate (design-dependent). An open circuit reads infinite resistance.

Diagnostic algorithm

Read and record all related DTCs and freeze-frame data; note times and system state when fault set.
Confirm safety: disable HV system and follow manufacturer isolation procedures before inspecting or disconnecting HV components.
Visual inspection: inspect negative contactor assembly, connectors, wiring harness, and signs of overheating or corrosion.
Check fuses/relays: verify auxiliary and contactor-related fuses/relays are present and functional.
With vehicle safe for diagnostics, command the contactor ON using a scan tool and observe command status and any feedback bits.
Measure voltage at the contactor control terminal while commanded ON. If no voltage, trace back to driver module and check connector/power supply.
With HV isolated and discharged per procedure, measure coil resistance across the contactor coil. Open (infinite) indicates a failed coil or open harness.
Perform continuity checks from the control module output pin to the contactor connector pin. Repair any open/short circuits found.
If wiring and connectors are good and coil resistance is correct but no operation occurs, test or replace the controlling module output stage or swap with a known-good module if possible.
After repairs, clear codes, attempt normal charging operation, and verify DTC does not return and that charging/contactors operate correctly.
Note: Always follow manufacturer-specific service manuals and HV safety procedures when working on battery/contactors.

Likely causes

Broken/disconnected harness or terminal at the negative contactor
Failed contactor coil (open coil winding)
Faulty low-side/high-side driver in the module controlling the contactor
Connector corrosion or pin pushed out at contactor or ECU
Protective fuse or current-sensing device open

Fault status

⚠️ Status

Control circuit open for Battery Charging System Negative Contactor D — contactor commanded but open/no continuity detected. Charging may be disabled and a high-voltage system warning may be present.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours