B1302

Code

ALFA ROMEO B — Body

Accessory timer relay circuit

Brand: ALFA ROMEO

Type: B — Body

Views: UK: 22 EN: 131 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Blown fuse supplying accessory/timer relay
Failed accessory timer relay (stuck open or closed)
Open, short, or high-resistance wiring in the relay supply, control, or ground circuit
Corroded or loose relay connector or wiring terminals
Faulty body control module / timer module output
Water ingress or damage to connector or relay

Symptoms

Accessories (radio, windows, interior lights, etc.) do not remain powered as expected after ignition-off
Accessories do not operate when they should or operate intermittently
Accessory unit(s) fail to turn on at all
Possible battery drain if relay is stuck closed
Related warning or information messages on dash
DTC B1302 stored and may be accompanied by other body electrical codes

What to check

Read and record all stored codes and freeze-frame data with a scan tool
Check battery voltage (should be ~12–14.5 V) and charging system condition
Inspect fuses related to accessory/timer circuits for proper rating and continuity
Visually inspect relay, relay socket, and wiring for corrosion, damage or loose connectors
Check for obvious water ingress or physical damage at relay and module connectors
Using a scan tool or data list, monitor the accessory timer output/status while operating relevant functions

Signal parameters

Supply voltage to relay: should be battery voltage (approx. 11–14.5 V) with key on and when timer feeds are active
Control signal from control module: either switched to ground or switched 12 V depending on design; should appear when timer is commanded
Relay coil continuity: typically low ohms (tens to a few hundred ohms) — should show continuity, not infinite or very high resistance
Ground: low resistance to chassis ground at relay/connector (near 0 Ω)
No-load contact side: when relay energized, switched output should present battery voltage to accessory circuits

Diagnostic algorithm

Connect a diagnostic scanner, record B1302 and any other codes, then view live data related to the accessory timer/relay output.
Verify battery voltage and ensure good battery state. Low battery can cause spurious body module faults.
Locate accessory timer relay and associated fuses; perform visual inspection of relay, socket, wiring, and connectors for damage or corrosion.
Check related fuse(s) for continuity and correct rating; replace blown fuses only after finding the root cause.
With ignition in the appropriate position and accessories commanded, measure supply voltage at the relay power pin — should be battery voltage.
Command the accessory timer (or simulate conditions) and observe the control signal at the relay coil control pin: verify it switches (to ground or +12 V) as expected.
Measure coil resistance with relay removed: expect low ohms (continuity). If open or out of range, bench-test or swap relay with identical known-good relay.
Check continuity between relay output and accessory loads, and continuity of ground circuit; repair any open/shorts found.
If wiring and relay test good but control signal is absent or abnormal, check output driver at the control module connector for shorts to power or ground. Perform module connector pin inspection and wiggle tests to reproduce fault.
If module output is faulty, confirm with manufacturer-specific module tests before replacing the control module. Replace relay/repair wiring as necessary.
After repairs, clear codes, cycle ignition and perform a functional test and road/soak test to ensure intermittent faults do not recur.

Likely causes

Blown 12V fuse in accessory/timer feed
Accessory timer relay coil or contacts failed
Broken or chafed wire between relay and control module or battery
Connector pins corroded, bent, or not seated
Control module driver transistor for the relay is open or shorted
Intermittent failure caused by moisture in the relay housing

Fault status

⚠️ Status

Accessory timer relay circuit fault detected. The body/timer control unit reports abnormal voltage, open/short, or unexpected state on the accessory timer relay circuit. Convenience functions controlled by the timer may not operate correctly.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-1.5 hours

Similar codes

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email