Code
B1303
ALFA ROMEO
B — Body
Accessory timer relay open circuit
AI status
Completed
Completed
100%
Causes
- Blown fuse for accessory/timer circuit
- Open or damaged wiring between relay and body control module (BCM)
- Faulty accessory timer relay (stuck open or coil open)
- Corroded or loose relay socket or connector pins
- Faulty BCM or module output driver (rare)
- Poor ground at relay or module
Symptoms
- Accessories (radio, windows, power outlets) do not remain powered as expected after ignition off
- Accessories not powered at all when ignition/accessory position selected
- Intermittent accessory operation or only while ignition is on
- Malfunction message or stored body control DTC
- No accessory feed voltage present at relay socket
What to check
- Read and record freeze-frame and any related body/BCM DTCs with a scan tool
- Visually inspect relay, relay socket, harness and related fuses for damage or corrosion
- Check accessory/timer fuse(s) for continuity and correct rating
- Backprobe relay socket: verify control voltage from BCM and battery feed with ignition in ON/ACC and OFF positions
- Check continuity to ground from relay ground terminal
- Wiggle wiring harness while monitoring to reproduce intermittent opens
Signal parameters
- Battery supply voltage at relay feed: ~12.0–14.5 V with ignition ON
- Control/coil drive from BCM: logic-level 0 V (off) or battery voltage (~12 V) when activated (may be switched to ground instead on some vehicles)
- Coil resistance (typical): 50–200 ohms (varies by relay) — open coil reads infinite ohms
- Contact continuity when relay energized: near 0 ohms; open when de-energized
Diagnostic algorithm
- Connect a scan tool, read DTCs and note any related body control codes. Clear the code and attempt to re-create the fault to confirm persistence.
- Visually inspect associated fuses, relay and harness for damage, corrosion or loose connectors. Replace any blown fuses and clean/secure connectors.
- With ignition OFF and key/scan tool in required position, measure battery voltage at the relay feed terminal. Confirm presence of battery feed where expected.
- Energize the accessory timer (use ignition ACC/ON or command via scan tool) and backprobe control terminal at relay socket. Verify signal changes (0 ↔ 12 V) per vehicle wiring diagram. If no control signal, suspect BCM or wiring open.
- Check relay coil resistance on the bench or in-socket (with power removed). Infinite resistance = open coil — replace relay.
- Check continuity of wiring between relay and BCM and between relay and ground. Repair any open circuits or high-resistance connections.
- If wiring and relay check good but no control drive from BCM, inspect BCM connectors for corrosion or bent pins. If connector and wiring are OK, further module testing or replacement may be required per manufacturer procedures.
- After repair, clear DTCs and verify proper accessory timer operation under normal conditions and that code does not return.
Likely causes
- Corroded/loose relay connector or terminal
- Open feed or ground wire to relay
- Defective accessory timer relay
- Blown inline fuse protecting the relay coil or contact
Fault status
Status
Accessory timer relay open circuit detected — accessory timer not functioning.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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