OBD Code B1620: PATS Transceiver Signal Not Received

The OBD-II diagnostic trouble code B1620 is a body system code that specifically relates to your vehicle’s PATS (Passive Anti-Theft System) transceiver module. When this code is triggered, it means your vehicle’s onboard computer has detected that the PATS transceiver is not properly sending or receiving the radio frequency signal needed to communicate with your key fob and authorize engine start. This is a security-related code that can prevent your vehicle from starting if not addressed.

What Does Code B1620 Mean?

The PATS system is a passive anti-theft technology found primarily in Ford, Lincoln, and Mercury vehicles. It uses radio frequency identification (RFID) technology to communicate between your vehicle key and a transceiver module mounted near the steering column. The transceiver sends a signal to your key fob, which responds with a unique code. If the codes match, the engine is allowed to start.

Code B1620 specifically means the PATS transceiver module is failing to send or receive this critical signal. The vehicle’s body control module (BCM) or security module has detected a communication failure with the transceiver. This could indicate:

• The transceiver module itself is defective or has failed
• Electrical power or ground issues affecting the transceiver
• Wiring damage or loose connections to the transceiver
• A faulty key fob that isn’t responding to the transceiver signal
• Software or programming issues with the security system

Common Symptoms

When code B1620 is present, you may experience:

• Engine won’t start: The vehicle may refuse to crank or start, even with a valid key
• Intermittent starting issues: The vehicle starts sometimes but not consistently
• Check Engine Light or Security Light: Dashboard warning lights illuminate
• Key fob not working: Remote lock/unlock functions may fail
• Clicking sound when turning the key: Starter attempts to engage but engine won’t fire
• Vehicle stuck in “limp mode”: Engine may run but with reduced performance
• Difficulty programming new keys: Attempts to add spare keys fail

Possible Causes (Ranked by Frequency)

1. Defective PATS Transceiver Module (Most Common): The transceiver module itself has failed or is malfunctioning. This is the most common cause and typically requires replacement.
2. Faulty Key Fob: The key fob battery is dead, the fob is damaged, or the internal circuitry has failed. A key fob that doesn’t respond to the transceiver signal will trigger this code.
3. Loose or Corroded Wiring Connections: The connectors to the transceiver module may be loose, corroded, or improperly seated, disrupting signal transmission.
4. Damaged Wiring Harness: Wiring leading to the transceiver module may be cut, pinched, or damaged, breaking the electrical circuit.
5. Electrical Power Supply Issues: The transceiver module may not be receiving adequate power due to a blown fuse, faulty relay, or battery issues.
6. Ground Connection Problems: A poor or missing ground connection can prevent the transceiver from functioning properly.
7. Software or Programming Glitch: The vehicle’s security system software may need to be updated or the system may need to be reprogrammed.
8. Water Damage or Moisture Intrusion: Moisture inside the transceiver module or its connectors can cause signal loss.
9. Steering Column Damage: Since the transceiver is mounted near the steering column, collision damage or impact can break internal components.

Diagnostic Steps

Follow these steps to diagnose code B1620:

Step 1: Check the Key Fob Battery

Start with the simplest solution. Replace the battery in your key fob with a fresh one. Many B1620 codes are caused by a dead fob battery preventing proper signal response. If you have a spare key, test it as well.

Step 2: Inspect the PATS Transceiver Connector

Locate the PATS transceiver module (typically mounted under the steering column or in the steering column shroud). Visually inspect the electrical connector for:

• Loose or partially disconnected pins
• Corrosion or oxidation on the connector
• Water damage or moisture inside the connector

If corrosion is present, carefully clean the connector pins with electrical contact cleaner. Reseat the connector firmly.

Step 3: Check Power and Ground

Using a multimeter, verify that the transceiver module is receiving power (typically 12V) and has a good ground connection. Check the relevant fuses in your vehicle’s fuse panel. A blown fuse will prevent the transceiver from operating.

Step 4: Inspect Wiring for Damage

Carefully examine the wiring harness leading to the transceiver module for:

• Cuts or pinches in the insulation
• Exposed wires
• Signs of rodent damage
• Improper routing that could cause chafing

Step 5: Attempt System Reprogramming

Many Ford vehicles allow you to reprogram the PATS system yourself by turning the ignition on and off in a specific sequence. Consult your vehicle’s owner manual for the exact procedure. This can sometimes resolve software-related issues.

Step 6: Use a Diagnostic Scanner

Connect an OBD-II scanner with PATS diagnostic capability to read additional fault codes and data. This will help pinpoint whether the issue is with the transceiver module, key fob, or wiring.

Step 7: Professional Diagnosis

If the above steps don’t resolve the issue, the transceiver module likely needs replacement. A Ford dealership or qualified technician can perform module replacement and reprogram the vehicle’s security system.

Repair Cost Estimates

The cost to repair code B1620 varies depending on the root cause:

• Key Fob Battery Replacement: $5–$15 (DIY) or $20–$50 (at a dealer)
• Connector Cleaning/Reseating: $0 (DIY) or $50–$100 (at a shop)
• Wiring Repair: $100–$300 depending on the extent of damage
• PATS Transceiver Module Replacement: $200–$600 for the module plus $100–$300 for labor, totaling $300–$900
• Fuse or Relay Replacement: $20–$100
• System Reprogramming (Dealership): $50–$150

Note: Ford dealerships typically charge more than independent shops. Getting multiple quotes is recommended.

Can I Still Drive?

Severity: Medium to High

Whether you can drive with code B1620 depends on the specific circumstances:

• If the engine won’t start: You cannot drive the vehicle at all. The security system is preventing engine operation as designed.
• If the engine starts but the code is present: You may be able to drive, but the vehicle’s security system is compromised. The engine could shut down unexpectedly if the transceiver loses signal.
• Safety concern: Do not rely on the vehicle for long trips until the issue is resolved. The vehicle could become stranded if the transceiver fails completely while driving.

Recommendation: Treat this code as a priority repair. Have it diagnosed and fixed as soon as possible to restore full vehicle functionality and security system integrity.

Frequently Asked Questions