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Home >> Pontiac >> 2005 >> Aztek Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 90 (Cruise Control System) >> Diagnostic Information and Procedures >> Cruise Control Inoperative/Malfunctioning >> Test Description
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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic path.

  1. 29:  DTCs will set in the PCM when you perform this diagnostic table.
Cruise Control Inoperative/Malfunctioning

Step Action Values Yes No
Schematic Reference: Cruise Control Schematics 
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views in Engine Controls - 3.8L (L26 and L32)
1 Did you perform the Cruise Control Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Cruise Control 
2 Is DTC P0573 current in the PCM? - Go to DTC P0573 in Lighting Systems Go to Step 3 
3
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Turn the cruise control On/Off switch OFF.
  4. With the scan tool, observe the following cruise control parameters in the Cruise Control data list:
    • Cruise On/Off Switch
    • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch
Do any of the parameters listed above display On?		 - Go to Step 13  Go to Step 4 
4
  1. With the scan tool, observe the Cruise On/Off Switch parameter.
  2. Turn the cruise On/Off switch ON.
Does the Cruise On/Off Switch parameter display On?		 - Go to Step 5  Go to Step 14 
5
  1. With the scan tool, observe the Cruise Set/Coast Switch parameter.
  2. Press and hold the set/coast switch.
Does the Cruise Set/Coast Switch parameter display On?		 - Go to Step 6  Go to Step 21 
6
  1. With the scan tool, observe the Cruise Resume/Accel Switch parameter.
  2. Press and hold the resume/accel switch.
Does the Cruise Resume/Accel Switch parameter display On?		 - Go to Step 7  Go to Step 21 
7
  1. Turn OFF the ignition.
  2. Disconnect C3 at the body control module.
  3. Turn ON the ignition, with the engine OFF.
  4. With a DMM, measure the voltage of the cruise control cancel signal circuit.
Does the voltage measure at or greater than the specified voltage?		 0.5 V Go to Step 12  Go to Step 8 
8
  1. Activate and hold the cruise control cancel switch.
  2. With a DMM, measure the voltage of the cruise control cancel signal circuit.
Does the voltage measure at the specified voltage?		 B+ Go to Step 9  Go to Step 20 
9
  1. Turn OFF the ignition.
  2. Connect C3 at the BCM.
  3. Disconnect the throttle actuator control (TAC) module.
  4. Turn ON the ignition, with the engine OFF.
  5. With a DMM, measure the voltage of the vehicle speed signal circuit.
Does the voltage measure greater than the specified value?		 8.5 V Go to Step 10  Go to Step 17 
10 Test the vehicle speed signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 11 
11 With a DMM, measure the voltage of the stop lamp switch signal circuit.
Does the voltage measure greater than the specified value?		 8.5 V Go to Step 23  Go to Step 24 
12 Test the cruise control cancel signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 21 
13
  1. Turn OFF the ignition.
  2. Disconnect the cruise switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the following cruise control parameters:
    • Cruise On/Off Switch
    • Cruise Resume/Accel Switch
    • Cruise Set/Coast Switch
Do any of the parameters listed above display On?		 - Go to Step 18  Go to Step 21 
14
  1. Turn OFF the ignition.
  2. Disconnect the cruise switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the ignition 1 voltage circuit and a good ground.
Does the test lamp illuminate?		 - Go to Step 15  Go to Step 25 
15 Test the ignition 1 voltage circuit for an open or for a high resistance between C201 and the cruise control switch. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 16 
16
  1. Turn OFF the ignition.
  2. Connect a 3 ampere fused jumper between the ignition 1 voltage circuit and the cruise control set/coast and resume/accelerate switch signal circuit.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Cruise Mode Signal parameter in the PCM Cruise Control data list.
Does the Cruise Mode Signal parameter display at or greater than the specified voltage?		 4.5 V Go to Step 21  Go to Step 19 
17 Test the vehicle speed signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 22 
18 Test the cruise control set/coast and resume/accel switch signal circuit for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 22 
19 Test the cruise control set/coast and resume/accel switch signal circuit for an open, for a short to ground, or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 22 
20 Test the cruise control cancel signal circuit for a short to ground, for an open, or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 21 
21 Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 26 
22 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and toConnector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 28 
23 Inspect for poor connections at the harness connector of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 29  Go to Step 27 
24 Repair the open or the high resistance in the stop lamp switch signal circuit between the underhood fuse block and the TAC module. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 29  -
25 Repair the open, the short to ground, or the high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 29  -
26 Replace the cruise control switch. Refer to Cruise Control Switch Replacement .
Did you complete the replacement?		 - Go to Step 29  -
27 Replace the TAC module. Refer to Throttle Body Assembly Replacement (L26)Throttle Body Assembly Replacement (L32) in Engine Controls - 3.8L (L26 and L32).
Did you complete the replacement?		 - Go to Step 29  -
28
IMPORTANT: Program the replacement PCM.
Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 3.8L (L26 and L32).Did you complete the replacement?		 - Go to Step 29  -
29 
  1. Enable the inflatable restraint steering wheel module. Refer to SIR Disabling and Enabling Zone 3 in SIR.
  2. Use the scan tool in order to clear the PCM DTCs.
  3. Operate the cruise control system in order to verify the repair.
Does the cruise control system operate properly?		 - System OK Go to Step 2 
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