For 1990-2009 cars

# SMU - Add DTC P0504

Subject: | Service Manual Update -- Add DTC P0504

Models: | 2003-2004 Saturn L-Series Vehicles

| 2003-2004 Saturn VUE Vehicles

| with 3.0L or 3.5L V-6 Engine (VINs R, B, 4 -- RPOs L81, L66)

Attention: | Fixed Operations Manager and Technician

### Purpose

The purpose of this bulletin is to inform Saturn technicians of an additional diagnostic procedure for Diagnostic Trouble Code (DTC) P0504. This information is not presently in the printed Service Manuals for 2004 Saturn L-Series vehicles and 2004 Saturn VUE vehicles, and was not previously available in SI for 2003-2004 Saturn L-Series and 2003-2004 VUE vehicles.

Please obtain all copies of the 2004 Saturn L-Series Service Manuals, Vol. 1 and 2004 Saturn VUE Service Manuals, Vol. 1. Make copies of the following information and insert into the Engine Controls - 3.0L (L81) section of the 2004 Saturn L-Series Service Manual, Vol. 1 and the Engine Controls - 3.5L (L66) section of the 2004 Saturn VUE Service Manual, Vol. 1. (This information is already present in the printed versions of the 2002-2003 Saturn L-Series and VUE Powertrain Electrical Diagnostics Service Manuals.)

The SI website will be updated immediately and future Service Stall System SI CD releases will include this and other Service Manual updates.

### DTC P0504

(SI Document ID #1485781 [L-Series] or 1486434 [VUE])

### Circuit Description

The engine control module (ECM)/powertrain control module (PCM) monitors the stop lamp switch signal circuit and the cruise control release signal circuit every 100 ms. The ECM/PCM monitors the status of the stop lamp switch signal circuit and the cruise control release signal circuit to see if they match when the brake pedal is pressed or released.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

The status of the stop lamp switch input to the ECM/PCM, and the cruise control release input to the ECM/PCM do not match for at least 2 seconds continuously, for 10 occurrences. Each time the signals match then do not match a counter increments. When the counter reaches 10, the DTC will set.

### Action Taken When the DTC Sets

When DTC P0504 is set the following will occur:

• | The cruise control is disabled.

• | The ECM/PCM will function as if the brake pedal is not pressed.

• | The control module stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The control module records the operating conditions at the time the diagnostic fails. The control module stores the information in the Failure Records.

### Conditions for Clearing the DTC

• | The DTC will clear when the status of the stop lamp switch input to the ECM/PCM and the cruise control release input to the ECM/PCM match for at least 2 seconds continuously for both the pressed position and the released position.

• | A current DTC Last Test Failed clears when the diagnostic runs and passes.

• | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

• | Clear the DTC with a scan tool.

### Diagnostic Aids

• | Inspect for proper adjustment of the stop lamp switch and cruise/brake switch. Refer to Cruise Release Switch Adjustment in Cruise Control and Stop Lamp Switch Adjustment.

• | Check for intermittent and poor connections. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Exterior Lights Schematics and Cruise Control Schematics in Cruise Control. Connector End View Reference: Master Electrical Component List in Wiring Systems.
1 | Did you perform the Diagnostic System Check-Lighting Systems ? | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems
2 |

1. With the scan tool, observe the Brake Switch parameter and the Cruise Brake Switch parameter.
2. Press and release the brake pedal.

Does the Brake Switch parameter and Cruise Brake Switch parameter display change closely with each other?

Go to Diagnostic Aids

Go to Step 3

3 |

1. With the scan tool, observe the Cruise Brake Switch parameter.
2. Press and release the brake pedal.
3. Turn the ignition ON with the engine OFF.
4. Observe the fuel tank pressure (FTP) sensor voltage with a scan tool.

Does the Cruise Brake Switch parameter display change with the brake pedal position?

Go to Step 6

Go to Step 4

4 |

1. Turn OFF the ignition.
2. Disconnect the cruise/brake switch.
3. Turn ON the ignition, with the engine OFF.

Does the Cruise Brake Switch parameter display Applied?

Go to Step 5

Go to Step 12

5 |

1. Turn OFF the ignition.
2. Connect a 10-amp fused jumper between the ignition positive voltage circuit of the cruise/brake switch and the cruise control release signal circuit of the cruise/brake switch.
3. Turn ON the ignition, with the engine OFF.

Does the Cruise Brake Switch parameter display Released?

Go to Step 16

Go to Step 8

6 |

1. Turn OFF the ignition.
2. Disconnect the stop lamp switch.
3. Turn ON the ignition, with the engine OFF.
4. With the scan tool, observe the Brake Switch parameter.

Does the Brake Switch parameter display Released?

Go to Step 7

Go to Step 10

7 |

1. Turn OFF the ignition.
2. Connect a 15-amp fused jumper between the battery positive voltage circuit of the stop lamp switch and the stop lamp switch signal circuit.
3. Turn ON the ignition, with the engine OFF.

Does the Brake Switch parameter display Applied?

Go to Step 15

Go to Step 11

8 | Test the ignition positive voltage circuit of the cruise/brake switch for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 9
9 | Test for an open, high resistance, or short to ground in the cruise control release signal circuit of the cruise/brake switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14
10 | Test the stop lamp switch signal circuit for a short to voltage. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14
11 | Test the battery positive voltage circuit of the stop lamp switch for an open, high resistance, or short to ground. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 13
12 | Test the cruise control release signal circuit of the cruise/brake switch for a short to voltage. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 17
13 | Test the stop lamp switch signal circuit for an open, high resistance, or short to ground. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 14
14 | Inspect for poor connections at the harness connector of the engine control module (ECM)/powertrain control module (PCM). Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 17
15 | Inspect for poor connections at the harness connector of the cruise/brake switch. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 18
16 | Inspect for poor connections at the harness connector of the stop lamp switch. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 19
17 | Important: Program the replacement ECM/PCM. Replace the ECM/PCM. Refer to Engine Control Module (ECM) Replacement/Powertrain Control Module (PCM) Replacement in Engine Controls. Did you complete the replacement? | Go to Step 20 | --
18 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 20 | --
19 | Replace the cruise/brake switch. Refer to Cruise Release Switch Replacement in Cruise Control. Did you complete the replacement? | Go to Step 20 | --
20 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the Vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK