Code
P1517
DS
P — Powertrain
Engine immobiliser function
Views:
UK: 1
EN: 3
RU: 7
AI status
Completed
Completed
100%
Causes
- Fault in the immobiliser/anti-theft system
- Loss of communication between immobiliser module and engine control module (ECU)
- Invalid or unreadable key transponder signal
- Power, ground, or fuse fault to immobiliser components
- Software or programming mismatch after module replacement
Symptoms
- Engine will not crank or starter disabled
- Engine cranks but will not start or stalls immediately
- Immobiliser or security warning lamp illuminated on dash
- Intermittent no-starts or start allowed only occasionally
- Communication errors relating to immobiliser on a scan tool
What to check
- Read all related fault codes with a manufacturer-capable scan tool and record freeze frame data
- Inspect key(s) for physical damage and test with spare known-good key
- Check battery voltage and charging system; low voltage can affect immobiliser
- Verify fuses and power/ground at the immobiliser control module and ECU
- Visually inspect wiring and connectors for damage, corrosion, or disconnection
- Check for immobiliser/warning lamp behavior during key on and cranking
Signal parameters
- Key transponder ID read status (valid/invalid)
- Immobiliser antenna coil output and continuity
- Power supply voltage to immobiliser module (12V under key-on)
- Ground continuity for immobiliser module
- CAN bus or serial communication between immobiliser and ECU (message presence)
- ECU immobiliser enable/disable output or immobiliser request signal
Diagnostic algorithm
- Read and record P1517 and any related codes; clear codes and attempt to reproduce to confirm persistence.
- Verify battery voltage is within specification. Recharge or replace if low before further testing.
- Check fuses and relays supplying the immobiliser and ECU; replace any blown fuses and re-test.
- Inspect keys and try a known-good or spare key. If spare works, suspect key transponder damage.
- Inspect immobiliser antenna/reader at the ignition for damage; measure coil continuity and compare to spec.
- With scan tool, observe immobiliser module status and communication messages on CAN/diagnostic data bus. Note any communication timeouts or errors.
- Verify power and ground at the immobiliser module and at the ECU pins. Repair wiring as required.
- If wiring and power/ground are good but system still faults, follow manufacturer procedure to perform key/immobiliser re-learn or reprogramming.
- If reprogramming does not restore function, swap or bench-test immobiliser module per manufacturer guidance, or consult dealer-level diagnostics for module replacement/coding.
- After repairs or programming, clear codes and verify normal operation over multiple cycles; document final status.
Likely causes
- Defective key transponder or damaged key
- Faulty immobiliser antenna/reader (key coil) near ignition
- Damaged immobiliser control module or ECU immobiliser interface
- Broken wiring, connectors, or low battery voltage affecting immobiliser
- Incorrect immobiliser/ECU coding or failed software update
Fault status
Status
Immobiliser fault detected — engine start inhibited or immobiliser function degraded.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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