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For 1990-2009 cars only

Keyless Entry System Inoperative Active

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The active keyless entry system is considered to be the device to control the following: door locking/unlocking, trunk access, and panic function. The keyless entry system will unlock the vehicle doors or open the rear compartment when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the keyless entry transmitter sending a radio frequency signal to the external RF antenna located in the back glass. This antenna is connected via coax cable to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via serial data message. Poor performance of the system may be due to:

    • Insufficient connection of the external RF Antenna to the RCDLR
    • Low transmitter battery
    • Radio Frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc
    • High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders

Diagnostic Aids

For the J 43241 Keyless Entry Tester, inspect the keyless entry transmitter part number to determine that it is the correct model for the vehicle. A wrong model transmitter may pass the test, but it will not activate the vehicle remote system.

Reference Information

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Keyless Entry System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 43241 Keyless Entry Tester

Circuit/System Verification

Attempt to program the keyless entry transmitter, refer to Transmitter Programming. The transmitter should program.

Circuit/System Testing

  1. Verify that the transmitter is the correct transmitter for the vehicle.
  2. If not the correct transmitter, replace the transmitter.
  3. Verify the scan tool FOB Programmed parameter for the appropriate transmitter is Yes.
  4. If not the specified value, program the transmitter. Refer to Transmitter Programming.
  5. Place the transmitter on the test pad of the J 43241 and press each transmitter button one at a time. The tester should sound a tone and illuminate a green light with each button press.
  6. If one or more buttons does not sound the tone and illuminate the green light, replace the transmitter battery and retest with the J 43241 . If the condition continues after battery replacement, replace the transmitter.
  7. Inspect the external RF antenna connection at the RCDLR. First, gently pull on the coax connector at the module. If the coax comes out, then it wasn’t seated properly. Remove and carefully inspect the coax connection for bent blades or a bent center pin. Fix coax connection if necessary and re-seat connector until a "click" is heard. Gently pull on the coax connection to make sure it is seated properly.
  8. Operate the transmitter while observing the scan tool Fob Function parameter for the appropriate transmitter. The parameter should correspond with the function selected on the transmitter.
  9. If the parameter does not match the function selected on the transmitter, replace the transmitter.
  10. Attempt to program the transmitter, refer to Transmitter Programming. The transmitter should program.
  11. If the transmitter does not program, test the keyless entry antenna for an open/high resistance. If the circuit tests normal, replace the RCDLR.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Transmitter Programming
    •  Control Module References for RCDLR replacement, setup, and programming

Keyless Entry System Inoperative Passive

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Keyless Entry Antenna - Signal (4)

B3119 02

B3119 05

B3119 05

--

Keyless Entry Antenna - Low Reference (4)

--

B3119 05

--

--

Keyless Entry Antenna - Signal (5)

B3120 02

B3120 05

B3120 05

--

Keyless Entry Antenna - Low Reference (5)

--

B3120 05

--

--

Keyless Entry Antenna - Signal (3)

B3121 02

B3121 05

B3121 05

--

Keyless Entry Antenna - Low Reference (3)

--

B3121 05

--

--

Keyless Entry Antenna - Signal (2)

B3123 02

B3123 04

B3123 04

--

Keyless Entry Antenna - Low Reference (2)

--

B3123 04

--

--

Keyless Entry Antenna - Signal (1)

B3123 02

B3123 04

B3123 04

--

Keyless Entry Antenna - Low Reference (1)

--

B3123 04

--

--

Keyless Entry Active Antenna Supply Voltage

B3122 04

B3122 04

B3122 04

--

Keyless Entry Active Antenna Data Signal

B3122 04

B3122 04

B3122 04

--

Keyless Entry Active Antenna Clock Signal

B3122 04

B3122 04

B3122 04

--

Keyless Entry Active Antenna Low Reference

--

B3122 04

--

--

Circuit/System Description

The passive portion of the keyless entry system is considered to be the starting and entry functions that do not require any buttons on the keyless entry transmitter to be pressed. The passive keyless entry antennas are used as short range low frequency (LF) transmitters. As an exterior door handle is pulled on a locked door, the keyless entry antenna transmitter broadcasts a challenge to the keyless entry transmitter that extends approximately 1 meter. If the response from the keyless entry transmitter via radio frequency (RF) is valid, the locked door will be passively unlocked/unlatched and allow the door to be opened. The front doors will open with one pull of the front door handle. The rear doors will unlock with the first pull of the door handle and unlatch with the second pull of the door handle. Similarly, when the start/stop button is pressed, the interior keyless entry antennas sends a challenge to the keyless entry transmitter to determine whether it is inside the vehicle. If the response from the transmitter is valid, the vehicle will start.

When the keyless entry transmitter responds, it sends a radio frequency signal to the external RF antenna located in the back glass. This antenna is connected via coax cable to the remote control door lock receiver (RCDLR). The RCDLR interprets the signal and activates the requested function via serial data message. Poor performance of the system may be due to:

    • Insufficient connection of the external RF Antenna to the RCDLR
    • Low transmitter battery
    • Radio Frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc
    • High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders

Reference Information

Schematic Reference

Remote Function Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Keyless Entry System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 43241 Keyless Enter Tester

Circuit/System Verification

  1. Ignition ON, observe the scan tool Ext. Driver Door Handle Switch, Ext. Psgr. Door Handle Switch, and Trunk Release Switch parameters while operating their respective release handle/touch pad. The parameter should change between Active and Inactive as commanded.
  2. If the parameter does not cycle between the specified values, refer to Power Door Latch System Malfunction.
  3. With the vehicle locked, attempt to passively unlock and access the vehicle at the left door, right door, and rear compartment by approaching the vehicle with a valid transmitter and operating their respective release handle/touch pad. Each door and the rear compartment should unlock/unlatch and open.
  4. If both doors and the rear compartment do not unlock/unlatch and open, refer to Passive Transmitter Malfunction.
    If only one door or the rear compartment does not unlock/unlatch and open, refer to Antenna Circuit Malfunction.

Circuit/System Testing

Passive Transmitter Malfunction

  1. Place the keyless entry transmitter on the J 43241 and approach the vehicle. Operate the release handle/touch pad. Verify the J 43241 sounds a tone.
  2. If the tone does not sound, press each transmitter button one at a time. If the tone still does not sound, replace the transmitter battery and retest with the J 43241 . If the condition continues after battery replacement, replace the keyless entry transmitter.
  3. If all circuits test normal, inspect the external antenna connection at the RCDLR. First, gently pull on the coax connector at the module. If the coax comes out, then it wasn't seated properly. Remove and carefully inspect the coax connection for bent blades or a bent center pin. Fix coax connection if necessary and re-seat connector until a "click" is heard. Gently pull on the coax connection to make sure it is seated properly.
  4. If all circuits test normal, test or replace the RCDLR.

Antenna Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the inoperative keyless entry antenna.
  2. Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal 1 (door handle) or the signal circuit terminal A (rear compartment) and ground.
  3. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RCDLR.
  4. Install a DMM between the signal circuit terminal 1 (door handle) or the signal circuit terminal A (rear compartment) and the low reference circuit terminal 2 (door handle) or the low reference circuit terminal B (rear compartment). Set the DMM to capture AC voltage using the MIN MAX function.
  5. Operate the release handle/touch pad Verify the DMM captured and AC voltage signal.
  6. 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.
  7. If all circuits test normal, test or replace the keyless entry antenna.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Outside Handle Replacement
    •  Ignition Lock Key Transmitter Antenna Replacement - Rear Compartment
    •  Control Module References for RCDLR replacement, setup, and programming