Initial Inspection and Diagnostic Overview

A Diagnostic System Check - Remote Keyless Entry:

CIRCUIT DESCRIPTION
The Remote Keyless Entry Diagnostic System Check is an organized approach to identify problems associated with the Remote keyless Entry (RKE) system. This check must be the starting point for any RKE complaint, and will direct you to the next logical step in diagnosing the complaint. Understanding the RKE system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

DIAGNOSTIC AIDS
^ The following conditions may result in an intermittent operation of the RKE system with no DTC stored:
- Any condition which results in the interruption of power to the receiver
- Weak or rundown battery
- Out of range battery or ignition voltage
Specification
Normal battery or ignition voltage: 9.0-16.0 V
- Weak transmitter battery
- A loose or damaged ground(s)
- An open or shorted serial data line
^ An intermittent malfunction in the electronic system may be very difficult to detect and to accurately diagnose. A good description of the complaint may be very useful in locating an intermittent fault condition. Faulty electrical connections or wiring causes most intermitting problems. When an intermitting condition is suspected, check the suspected circuits for the following conditions:
- Poor mating of connector halves or backed out terminals
- Improperly formed or damaged terminals
- Wire chafing
- Poor wire to terminal connections
- Dirty or corroded terminals
- Damage to connector bodies
^ If the transmitter range decreases or the transmitter does not operate, check for the following conditions:
^ Use the J 35616~ Connector Test Adapter kit whenever a diagnostic procedure requests terminal inspection or probing. Using the adapter ensures no damage to the terminal will occur, and will give an idea of whether contact tension is sufficient.
- Check if battery replacement is necessary
- Check for proper range (rainy or snowy weather decreases range)
- Check for obstructions (other vehicles or objects will decrease range)
- Electrical interference (cellular phones, power lines, radio towers, garage door openers, etc.)
- The transmitter is not programmed or synchronized to the vehicle
^ When a RKE system malfunction is corrected, clear the receiver's diagnostic memory to avoid reading the original DTC stored in the memory.
^ Inspect the power door locks and trunk release functions for proper operation. If the locks and/or trunk release do not function properly, repair them before diagnosing the RKE system.
^ Inspect that the transmitter battery terminals are clean and are making good contacts with the battery.
^ Try a second transmitter, if available. If the second transmitter operates, remove the battery and install the battery in the original and perform the synchronizing transmitter procedure. Try the original transmitter again. If the original transmitter operates, replace the battery. If the original transmitter still does not work, replace the original transmitter.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
1. This test determines if communications can be established with the RKE system.
2. This test checks for any RKE system DTCs stored in the receiver's memory.
3. This test determines if communications can be established with other systems connected to the same serial data line.
4. This test checks the operation of the transmitter in both the manual and passive positions.
5. This test checks the receiver's power circuit. If the test lamp does not light, there is an open in CKT A823.
6. This test checks the receiver's ground circuit. If the test lamp does not light, there is an open in the ground circuit.
7. This test checks for an open in the serial data line between the receiver and the BCM.