Electrical problems with my Peugeot 307 CC 2.0 2004
I am experiencing several strange electrical problems with my car.
Problem 1
The windshield wipers and headlights start operating by themselves without touching
The starter motor cranks normally, but the engine does not start.
Other symptoms:
The remote central locking does not work
The power windows work intermittently (they move in short steps)
For this issue, the BSI and BCM were already replaced, but the problem still exists.
Also, OBD diagnostic tools cannot communicate with the ECU at all.
Problem 2
When I lock the car with the remote key, everything seems normal.
But after 1–2 hours, the car enters “Economy Mode Active” and the remote control can no longer unlock the doors.
Problem 3
Diagnostic tools connected to the OBD port cannot communicate with any module.
They always show a communication error with the ECU, and no ECUs are detected.
Question
Has anyone experienced similar electrical problems with a Peugeot 307 CC?
Could this be a CAN bus wiring issue, a short circuit, or a network problem between BSI and ECU?
What We Have Tried So Far
Replaced Parts:
BSI (Built-in Systems Interface) — replaced and coded
BSM (Body Systems Module) — 3 different units tried
ABS Module — unplugged, fault continued
Checked / Cleaned Points:
Battery — 12.8 V, good
Alternator — 14.6 V, good
MC10 earth point — sanded to bare metal, direct earth wire added
MC12 earth point — was rusty, sanded to bare metal, direct earth wire added
BSM pin 12 (large green connector) — 12 V present, good
OBD socket — inspected
All BSI connectors — unplugged, cleaned and refitted
Diagnostic Tools:
PP2000 v7 and v9 — cannot connect, ECU communication error
Launch — connects successfully, BSI/ECU/ABS all show Normal
PP2000 gave these warnings on first connection attempt: "No permanent ve supply to ECU 1320" and "No post-ignition ve supply to ECU 1320"
Symptoms:
Wipers coming on by themselves
Headlights flashing by themselves
Remote key not working
Immobilizer not recognizing the key
Engine will not start
Economy mode active
Fault returns after 15-20 minutes
Fault clears after disconnecting battery for 2 hours, then returns
Vehicle Details:
Peugeot 307 CC 2004
Engine: 2.0 16V EW10J4
ECU: Magneti Marelli 6LP
AI: Have there been any aftermarket electrical accessories or modifications (such as alarms, stereos, trackers, etc.) installed on the car, either by you or a previous owner?
Yes, the car has had an aftermarket stereo and an alarm system installed by a previous owner, many years ago. The car has been connecting to PP2000 without any issues for years after these installations. The fault only started recently with no new modifications.
AI: Have you inspected the wiring harness for signs of damage, corrosion, or water ingress, particularly in areas like under the fuse box, door jambs, or footwells?
We have visually inspected the wiring harness in the engine bay and under the dashboard. No visible signs of damage, water ingress or corrosion were found. The OBD socket connector was also inspected and appeared clean. The footwells and door jambs were checked and no moisture was detected.
I am experiencing several strange electrical problems with my car.
Problem 1
The windshield wipers and headlights start operating by themselves without touching
The starter motor cranks normally, but the engine does not start.
Other symptoms:
The remote central locking does not work
The power windows work intermittently (they move in short steps)
For this issue, the BSI and BCM were already replaced, but the problem still exists.
Also, OBD diagnostic tools cannot communicate with the ECU at all.
Problem 2
When I lock the car with the remote key, everything seems normal.
But after 1–2 hours, the car enters “Economy Mode Active” and the remote control can no longer unlock the doors.
Problem 3
Diagnostic tools connected to the OBD port cannot communicate with any module.
They always show a communication error with the ECU, and no ECUs are detected.
Question
Has anyone experienced similar electrical problems with a Peugeot 307 CC?
Could this be a CAN bus wiring issue, a short circuit, or a network problem between BSI and ECU?
What We Have Tried So Far
Replaced Parts:
BSI (Built-in Systems Interface) — replaced and coded
BSM (Body Systems Module) — 3 different units tried
ABS Module — unplugged, fault continued
Checked / Cleaned Points:
Battery — 12.8 V, good
Alternator — 14.6 V, good
MC10 earth point — sanded to bare metal, direct earth wire added
MC12 earth point — was rusty, sanded to bare metal, direct earth wire added
BSM pin 12 (large green connector) — 12 V present, good
OBD socket — inspected
All BSI connectors — unplugged, cleaned and refitted
Diagnostic Tools:
PP2000 v7 and v9 — cannot connect, ECU communication error
Launch — connects successfully, BSI/ECU/ABS all show Normal
PP2000 gave these warnings on first connection attempt: "No permanent ve supply to ECU 1320" and "No post-ignition ve supply to ECU 1320"
Symptoms:
Wipers coming on by themselves
Headlights flashing by themselves
Remote key not working
Immobilizer not recognizing the key
Engine will not start
Economy mode active
Fault returns after 15-20 minutes
Fault clears after disconnecting battery for 2 hours, then returns
Vehicle Details:
Peugeot 307 CC 2004
Engine: 2.0 16V EW10J4
ECU: Magneti Marelli 6LP
AI: Have there been any aftermarket electrical accessories or modifications (such as alarms, stereos, trackers, etc.) installed on the car, either by you or a previous owner?
Yes, the car has had an aftermarket stereo and an alarm system installed by a previous owner, many years ago. The car has been connecting to PP2000 without any issues for years after these installations. The fault only started recently with no new modifications.
AI: Have you inspected the wiring harness for signs of damage, corrosion, or water ingress, particularly in areas like under the fuse box, door jambs, or footwells?
We have visually inspected the wiring harness in the engine bay and under the dashboard. No visible signs of damage, water ingress or corrosion were found. The OBD socket connector was also inspected and appeared clean. The footwells and door jambs were checked and no moisture was detected.
