B1601 – PATS Received Incorrect Key-Code From Ignition Key Transponder

The ODBII code B1601 indicates that the vehicle’s Passive Anti-Theft System (PATS) has received an incorrect key code from the ignition key transponder, preventing the engine from starting.

The severity of ODBII code B1601 is typically considered moderate.

Common Causes For: B1600 PATS Ignition Key Transponder Signal Is Not Received

• Faulty ignition key or transponder
• Damaged or worn key
• Malfunctioning ignition switch
• Issues with the PATS (Passive Anti-Theft System) module
• Poor electrical connections or wiring issues
• Incorrectly programmed key
• Interference from aftermarket devices
• Faulty vehicle computer or ECU

Common misdiagnosis for B1601 PATS Received Incorrect Key-Code From Ignition Key Transponder

• Faulty ignition switch
• Defective transponder key
• Malfunctioning keyless entry system
• Issues with the Body Control Module (BCM)
• Wiring or connection problems in the ignition system
• Faulty immobilizer system
• Incorrectly programmed key or fob
• Battery issues in the key fob
• Problems with the Engine Control Module (ECM)

Common Troubleshooting Steps

The OBD-II code B1601 indicates that the Powertrain Control Module (PCM) has received an incorrect key code from the ignition key transponder. This is often related to the Passive Anti-Theft System (PATS) in vehicles. Here are some common troubleshooting steps to address this issue:

• Check the Key:: **Inspect the Key:** Look for any physical damage or wear on the key. If the key is damaged, it may not be able to communicate properly with the transponder.
• **Use a Spare Key:** If available, try using a spare key to see if the issue persists. This can help determine if the original key is faulty.
• Check the Ignition Cylinder:: **Inspect the Ignition Cylinder:** Ensure that the ignition cylinder is functioning properly and that there are no obstructions or damage that could affect the key’s ability to turn.
• Check the Transponder:: **Test the Transponder:** If you have access to a transponder key tester, check if the transponder in the key is functioning correctly.
• **Reprogram the Key:** If the key is not recognized, it may need to be reprogrammed to the vehicle’s PATS system. This usually requires specialized equipment or a visit to a dealership.
• Inspect Wiring and Connections:: **Check Wiring:** Inspect the wiring and connectors related to the PATS system for any signs of damage, corrosion, or loose connections.
• **Look for Shorts or Opens:** Use a multimeter to check for continuity and ensure there are no shorts or open circuits in the wiring.
• Scan for Additional Codes:: **Use a Diagnostic Scanner:** Check for any additional trouble codes that may provide more context or indicate related issues with the PATS or other systems.
• Check the PATS Module:: **Inspect the PATS Module:** If the key and wiring are fine, the issue may lie with the PATS module itself. Check for any signs of damage or malfunction.
• **Reprogram or Replace the Module:** If necessary, the PATS module may need to be reprogrammed or replaced.
• Battery and Power Supply:: **Check the Battery:** Ensure that the vehicle’s battery is fully charged and in good condition, as low voltage can affect the operation of electronic systems.
• **Inspect Fuses:** Check the fuses related to the PATS and ignition systems to ensure they are not blown.
• Consult the Vehicle Manual:: **Refer to the Service Manual:** Consult the vehicle’s service manual for specific troubleshooting steps and wiring diagrams related to the PATS system.
• Professional Assistance:: **Seek Professional Help:** If the issue persists after performing these steps, it may be best to consult a professional mechanic or dealership with experience in PATS systems for further diagnosis and repair. By following these steps, you can systematically identify and resolve the issue related to the B1601 code.