Code
P1512
DS
P — Powertrain
Engine immobiliser function
AI status
Completed
Completed
100%
Causes
- Faulty or unrecognized transponder key or key fob
- Weak/flat key battery (if key has battery)
- Damaged or mispositioned immobiliser antenna/read coil (near ignition)
- Loss of power or ground to immobiliser module
- Blown fuse protecting immobiliser circuit
- Poor or lost CAN/vehicle network communication between immobiliser and engine control module
Symptoms
- Engine will not start (cranks but does not fire) or starter inhibited
- Security/immobiliser indicator lamp illuminated, flashing, or remaining on after key on
- Intermittent no-start condition
- No acknowledgement of key in hands-free or push-button start systems
- Other related DTCs or communication errors present on network scan
What to check
- Use a manufacturer-capable scan tool to read P1512 and any related freeze-frame data and stored codes
- Observe immobiliser/security indicator behaviour with ignition on
- Try a known-good or spare key and repeat start attempt
- Check vehicle battery voltage (approx. 12 V) and charging system; verify adequate supply during cranking
- Inspect fuses and relays for the immobiliser and related circuits
- Visually inspect wiring and connectors at ignition cylinder, antenna/read coil, immobiliser module and ECM for corrosion, damage or loose connections
Signal parameters
- Transponder read status: key ID present / not present
- Immobiliser module supply voltage ~12 V (battery voltage) and ground presence
- Antenna/read coil resistance — should not be open or short (refer to manufacturer values)
- CAN/diagnostic bus messages: immobiliser to ECM request/response present or absent
- Starter inhibit output state (active/inactive) reported by immobiliser module
- Security indicator lamp status (on/off/flashing) and count of flashes if diagnostic
Diagnostic algorithm
- Confirm and record DTC P1512 and any additional codes, note freeze-frame data
- Verify vehicle battery condition and ensure stable supply voltage during diagnosis
- Check immobiliser (security) lamp behaviour with ignition ON and when attempting to start
- Attempt to start using a spare or secondary programmed key; if spare works, suspect primary key or key programming
- Inspect and test antenna/read coil near ignition switch for secure mounting and continuity; repair wiring/connectors as required
- Verify power and ground at the immobiliser module and any inline fuses or relays; repair power/ground faults
- Scan the vehicle network for CAN/U-code communication faults between immobiliser and ECM; address any network issues first
- Use diagnostic tool to read transponder ID and compare to stored keys; if key not stored, perform manufacturer key registration/relearn procedure per service manual
- If all wiring, power and keys are correct and communication is present, consider immobiliser module or ECM fault — consult manufacturer repair information for module testing or replacement and required reprogramming
- After repairs, clear codes and perform key relearn/programming if required; verify successful starting and that code does not return
Likely causes
- Key not recognized by immobiliser (transponder ID mismatch)
- Dead or weak key battery preventing transponder transmission (if applicable)
- Antenna/read coil failure or wiring fault preventing key read
- Power/ground supply fault to immobiliser module
- Loss of communication between immobiliser module and ECM/PCM
Fault status
Status
Immobiliser fault detected: engine immobiliser function fault stored. Vehicle may be prevented from starting; security indicator may be active. Further diagnosis required.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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