Immobilizer to PCM Signal Error

What is P1259?

P1259 indicates a communication problem between your vehicle's immobilizer system and the Powertrain Control Module (PCM), which can prevent the engine from starting. This is a low-severity issue that primarily affects Honda models like the Accord and Civic, often triggered by key or security system malfunctions. Based on 347 reports, repairs average $6115, but DIY fixes are rare, attempted in only 5% of cases.

Common Causes

• ●Faulty immobilizer key or transponder (most common cause in Honda vehicles)
• ●Failed communication between the immobilizer control unit and PCM
• ●Wiring harness damage or connector issues in the security system circuit

Symptoms You May Notice

• ●Engine cranks but will not start (most frequently reported symptom)
• ●Check Engine Light illuminated on the dashboard
• ●Security or immobilizer warning light may be active

How to Fix It

• ●Replace or reprogram the immobilizer key and/or immobilizer control unit ($2700-$4900, high difficulty)
• ●Diagnose and repair wiring or connector faults in the immobilizer-PCM circuit ($cost varies, moderate difficulty)
• ●Replace the Powertrain Control Module (PCM) if it fails to recognize the immobilizer signal ($cost varies, high difficulty)