Key Fob Not Detected
Key Fob Not Detected
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The headliner and console passive antennas are located in the rear headliner area and in the center console. They are used as short range low frequency (LF) antennas. The headliner and console antennas are used to determine transmitter placement within the vehicle. When a valid keyless entry transmitter is within the passenger compartment, the headliner and console antennas broadcast a challenge within the passenger compartment to the transmitter. If the response from the transmitter via radio frequency (RF) is a valid response, the antenna will determine there is a fob within the vehicle. If no response is received, the antenna determines that no fob is in the vehicle.
The headliner and console passive antennas share a driver within the remote control door lock receiver (RCDLR) and are wired in parallel. The RCDLR has no way to determine which antenna is receiving a valid response from a transmitter, only that a valid response is being received.
Diagnostic Aids
Areas of high radio frequency (RF) traffic may cause an intermittent NO FOB DETECTED message. This is a normal condition. If the vehicle is parked in an area of high RF traffic, move vehicle before continuing with diagnostics.
Reference Information
Schematic Reference
Remote Function Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Keyless Entry System Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for Scan Tool Information
Circuit/System Verification
Important: This condition may be caused by low vehicle battery voltage. If the battery is not sufficiently charged (above 10 volts), the system will have difficulties detecting the fob and the NO FOBS DETECTED message will be displayed. Correct the low battery voltage condition to eliminate this condition.
1. With the vehicle locked, attempt to passively unlock and enter the vehicle by approaching the vehicle with a valid transmitter and pulling the exterior door handle. The door should unlock and open.
• If unable to enter the vehicle passively, refer to Keyless Entry System Inoperative (Active) (Keyless Entry System Inoperative (Active))Keyless Entry System Inoperative (Passive) (Keyless Entry System Inoperative (Passive)) .
2. While placing the keyless entry transmitter in various locations within the vehicle interior, verify the vehicle does not start.
• If the vehicle starts, inspect for any sources of RF interference such as cell phone chargers, power supplies, etc. that would interrupt transmitter and antenna communication.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the console passive antenna.
2. Place the key fob near the headliner antenna and attempt to start the vehicle. The vehicle should start.
• If the vehicle does not start, refer to Headliner Antenna Circuit Malfunction.
3. Refer to Console Passive Antenna Circuit Malfunction.
Headliner Antenna Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the headliner antenna.
2. Install a DMM between the signal circuit terminal A and the low reference circuit terminal B. Set the DMM to capture AC voltage using the MIN MAX function.
3. Attempt to start the vehicle. Verify the DMM captured an AC voltage signal.
• If an AC voltage was not captured, test the signal circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the RCDLR.
4. If all circuits test normal, test or replace the headliner antenna.
Console Passive Antenna Circuit Malfunction
1. Install a DMM between the signal circuit terminal A and the low reference circuit terminal B. Set the DMM to capture AC voltage using the MIN MAX function.
2. Attempt to start the vehicle. Verify the DMM captured an AC voltage signal.
• If an AC voltage was not captured, test the signal circuit and the low reference circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the RCDLR.
3. If all circuits test normal, test or replace the console passive antenna.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Rear) (Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Rear))Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Cup Holder) (Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Cup Holder))
* Ignition Lock Key Transmitter Antenna Replacement - Headliner (Ignition Lock Key Transmitter Antenna Replacement - Headliner)
* Control Module References (Programming and Relearning) for RCDLR replacement, setup, and programming