B1377

Code

FIAT B — Body

Oil change warning lamp circuit

Brand: FIAT

Type: B — Body

Views: UK: 19 EN: 26 RU: 24

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Page language: EN

Oil change or service reminder lamp does not illuminate during key-on bulb check
Lamp stays on continuously or illuminates intermittently
Unable to reset the oil change/service interval
Diagnostic trouble code B1377 stored in instrument cluster or body module
Possible inconsistent service reminders displayed in instrument cluster

Verify battery voltage is within normal range and reconnect battery if low
Scan all modules for related codes (instrument cluster, body control module, engine control module)
Inspect fuses related to instrument cluster and instrument illumination
Visually inspect wiring and connectors to the cluster and oil change reset switch for damage or corrosion
Check ground connections at the instrument cluster and nearby grounding points
Perform key-on bulb/LED check to confirm lamp operation

Use a diagnostic scanner to read and record all stored codes from the instrument cluster and body modules; note freeze-frame or snapshot data.
Verify battery voltage (12.4–12.8 V nominal with ignition off). Recharge or replace battery if low and retest.
Inspect and verify fuses related to the instrument cluster and exterior/interior lamps; replace any blown fuses and retest.
Perform a visual inspection of wiring and connectors to the instrument cluster, lamp circuit, and oil change/reset switch; repair any damaged wires, pins, or corroded connectors.
With ignition ON, perform a key-on bulb/LED check: verify the oil change lamp illuminates briefly. If not, probe for lamp supply voltage and ground at the cluster connector.
Check continuity between the cluster lamp pin and the lamp/ground; if open, trace and repair wiring faults. If short to ground/power present, isolate and repair.
If wiring and fuses are good, test or bench-check the instrument cluster lamp driver or replace the cluster if internal driver/LED has failed.
Scan CAN/LIN bus for communication errors; repair bus wiring or faulty module if messages related to service interval are missing or corrupt.
After repairs, clear DTCs, perform a service reset procedure if required, and confirm the lamp behavior during key-on and normal operation.
If fault persists after wiring and cluster replacement, check for software updates or programming requirements for the cluster/body module with dealer-level tools.

Blown fuse or poor battery/ignition supply to cluster
Damaged wiring harness at connectors (chafing, corrosion, pinback)
Failed LED/driver inside the instrument cluster
Intermittent ground or corroded connector at cluster or body module
Module communication error (CAN bus) or recent module replacement without programming

⚠️ Status

Oil change/service reminder lamp circuit fault detected — lamp may not illuminate correctly or may display incorrect service status.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2 hours

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