Diagnostic Aids
The theft deterrent system can be armed either by pressing the Lock button on the remote coded key or by the body control module (BCM) arming it automatically 30 seconds after the ignition is switched OFF. For arming to take place, both the driver's door and the passenger's door must be closed. When the system is armed, the powertrain control module (PCM) prevents the engine from being started.
The theft deterrent system can be disarmed by pressing the Unlock button on the remote coded key. This action unlocks both doors, turns on the interior lamp and disarms the system for 30 seconds, or opening the driver's door using the remote coded key and then inserting it into the ignition switch cylinder and turning the ignition to ON. This action permits the BCM to read the key's internal security code data via the remote coded key reader assembly.
Reading the key data is achieved via the ignition switch slip ring contact. If the system does not disarm when the ignition switch is turned on, as recognized by the security warning light emitting diode (LED) being extinguished, the Theft Deterrent system can be disarmed by pressing either the Lock or Unlock buttons on the remote coded key. Such a situation may occur if a misaligned or faulty key is being used.
The remote coded key is powered by its own internal battery. If the battery fails, the key reader circuitry within the ignition switch can provide power to the key when the key is inserted into the ignition cylinder and the ignition turned ON or it is turned to START.
When the Theft Deterrent system is armed by pressing the Lock button on the remote coded key, the external turn lamp indicators will flash once. From this point onward until the system is disarmed, the LED located within the instrument cluster will flash continually.
When the system is disarmed by pressing the Unlock button on the remote coded key, the turn indicators flash twice and the LED in the instrument cluster extinguishes.
When the ignition is turned to ON, the BCM then commences polling the PCM, via the powertrain interface module (PIM), for it to commence inspecting the remote coded-key security code. The key code is initially received directly from the key via the ignition switch slip ring, or remotely from the key via the remote key receiver. If the key is turned to the START position, initial engine cranking will commence, but the engine will not start until the key code has been verified by the PCM as being correct.
When the key code has been received from either the remote key receiver, or directly from the key via the BCM, the PCM then compares the received security code with its stored security code. If the 2 codes match, this then enables injector fuelling of the engine to commence. At this time, the PIM also sends an OK TO START message to the BCM.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Theft Deterrent System Schematics | ||||
1 | Did you review the Theft System Description and Operation and perform the necessary inspections? | -- | Go to Step 2 | |
2 |
Does the driver door only (2-stage unlock) or the doors (single-stage unlock) unlock? | -- | Go to Step 3 | |
3 |
Is the driver door ajar switch functioning correctly? | -- | Go to Step 4 | Go to Diagnostic Starting Point - Lighting Systems in Lighting Systems |
4 |
Is the passenger door ajar switch functioning correctly? | -- | Go to Step 5 | Go to Diagnostic Starting Point - Lighting Systems in Lighting Systems |
5 |
Does the key in the driver door switch unlock and lock both doors? | -- | Go to Step 6 | Go to Symptoms - Doors in Doors |
6 |
Does the driver door unlock (2-stage unlocking) or both doors unlock (single-stage unlocking)? | -- | Go to Step 7 | Go to Step 15 |
7 | In Step 6, did the left and right hand side indicator lamps flash twice? | -- | Go to Step 8 | Go to Step 15 |
8 | In Step 6, did the dome lamp illuminate? | -- | Go to Step 9 | Go to Diagnostic Starting Point - Lighting Systems in Lighting Systems |
9 | In Step 6, did the security warning light emitting diode (LED) extinguish immediately and begin flashing 30 seconds later? | -- | Go to Step 10 | Go to Step 19 |
10 | Operate the Lock button on the remote coded key within 4 meters of the driver side B-pillar. Did the dome lamp extinguish immediately after the lock button was activated? | -- | Go to Step 11 | Go to Diagnostic Starting Point - Lighting Systems in Lighting Systems |
11 | When locking the vehicle in Step 6, did the left and right hand side indicator lamps flash once? | -- | Go to Step 12 | Go to Step 44 |
12 | In Step 6, did the Security Warning LED commence flashing after locking was completed? | -- | Go to Step 13 | Go to Step 19 |
13 |
Does the security warning LED extinguish? | -- | Go to Step 14 | Go to Step 23 |
14 | Turn the ignition key to start the engine. Does the vehicle crank and start? | -- | System OK | Go to Step 33 |
15 | The audible alarm may sound during this step.
Do all indicator lamps flash twice? | -- | Go to Step 18 | Go to Step 16 |
16 |
Is the measurement equal to the specified value? | B+ | Go to Step 45 | Go to Step 17 |
17 |
Do all indicator lamps illuminate? | -- | Go to Step 19 | Go to Step 44 |
18 | Back-probe the hazard/theft indicator relay voltage supply circuit at the BCM connector with a voltmeter to ground. Refer to Measuring Voltage in Wiring Systems. Is the measurement equal to the specified value? | Battery Voltage | Go to Step 19 | Go to Step 46 |
19 |
Is the Security warning LED extinguished on the Instrument Cluster? | -- | The LED is functioning normally. System OK | Go to Step 20 |
20 | Disconnect the BCM connector C1 from the BCM. Is the Security warning LED still illuminated? | -- | Go to Step 21 | Go to Step 23 |
21 |
Is the Security warning LED extinguished on the Instrument Cluster? | -- | Go to Step 22 | Go to Step 47 |
22 |
Does the voltage remain at battery voltage while the security system is cycled? | -- | Go to Step 44 | Go to Step 48 |
23 | This test assumes that the remote coded key can gain access the vehicle but cannot start the engine from the ignition switch.
Does the security warning LED extinguish? | -- | System OK | Go to Step 24 |
24 |
Is the key contact pin making good contact? | -- | Go to Step 29 | Go to Step 49 |
25 |
Does the second key obtain access and start the engine OK? | -- | Replace original key. System OK | Go to Step 26 |
26 |
Is the measurement equal to the specified value? | B+ | Go to Step 27 | Go to Step 30 |
27 | With the slip ring surface isolated as in Step 26, measure the AC voltage between the ignition switch reader slip ring and a known good ground. Refer to Measuring Voltage in Wiring Systems. Is the measurement equal to the specified value? | 0-10 V | Go to Step 28 | Go to Step 29 |
28 | Back-probe between the ignition switch housing and a known good ground with an ohmmeter. Refer to Testing for Continuity in Wiring Systems. Is the value less than the value specified? | 1 ohms | Go to Step 29 | Go to Step 50 |
29 |
Does the scan tool display ON? | -- | Go to Step 30 | Go to Step 33 |
30 |
Is the measurement less than the value specified? | 1 ohms | Go to Step 31 | Go to Step 51 |
31 |
Is the measurement equal to the specified value? | 0-10 V | Go to Step 33 | Go to Step 44 |
32 |
Is the measurement equal to the specified value? | B+ | Go to Step 44 | Go to Step 52 |
33 |
Does TECH 2 display Disarm? | -- | Go to Step 38 | Go to Step 34 |
34 | Turn the ignition key to the START position. Does the engine crank and continue to crank after 1 second? | -- | Go to Step 38 | Go to Step 35 |
35 |
Is the measurement equal to the specified value when the key is in the start position? | B+ | Go to Step 36 | Go to Step 53 |
36 | With the scan tool still connected and ignition ON, exit Body Control Module and select Body/Powertrain Interface Module (PIM). Can the scan tool communicate with the PIM and display the software version number? | -- | Go to Step 37 | Go to Diagnostic Starting Point - Data Link Communications in Data Link Communications |
37 |
Does the scan tool display OFF for each of these items? | -- | Go to Step 38 | Go to Step 54 |
38 |
Is the measurement equal to the specified value? | B+ | Go to Step 39 | Go to Step 52 |
39 |
Does the engine crank? | -- | Go to Step 40 | Go to Step 54 |
40 |
Is the measurement less than the value specified? | 1 ohms | Go to Step 41 | Go to Step 55 |
41 | Check continuity of the primary serial data bus circuit between the BCM and the PIM with an ohmmeter. Refer to Testing for Continuity in Wiring Systems. Is the measurement less than the value specified? | 1 ohms | Go to Step 42 | Go to Step 56 |
42 |
Is the measurement less than the value specified? | 1 V | Go to Diagnostic Starting Point - Engine Electrical in Engine Electrical | Go to Step 43 |
43 |
Is the measurement less than the value specified when the vehicle is in Park or Neutral? | 1 ohms | Go to Step 43 | Go to Step 43 |
44 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the repair? | -- | Go to Step 59 | -- |
45 | Repair the left hand or right hand turn signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
46 | Repair an open or short to ground in the hazard theft indicator relay switch side battery feed circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
47 | Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console. Did you complete the repair? | -- | Go to Step 59 | -- |
48 | Repair a short to ground in the theft LED control circuit between the BCM and instrument cluster. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
49 | Inspect the key shaft and contact pin for damage. Did you complete the repair? | -- | Go to Step 59 | -- |
50 | Repair the ground circuit of the ignition switch. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
51 | Repair and open or short to ground in the ignition switch slip ring circuit between the switch slip ring and the BCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
52 | Repair the ignition switch ignition feed circuit between the ignition switch and the BCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
53 | Repair the start relay coil feed circuit between the ignition switch and the start relay or replace the relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
54 | Replace the PIM. Did you complete the repair? | -- | Go to Step 59 | -- |
55 | Repair an open in the PIM ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
56 | Repair the primary serial data bus circuit between the PIM and the BCM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
57 | Repair an open in the manual clutch position switch circuit (manual trans.) or the park/neutral position (PNP) switch circuit (auto. trans.) between the start relay and the PIM. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 59 | -- |
58 | Replace the manual clutch position switch circuit (manual trans.) or the PNP switch circuit (auto. trans.). Did you complete the repair? | -- | Go to Step 59 | -- |
59 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 1 |
