2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
P0571-BRAKE SWITCH 1 PERFORMANCE
CIRCUIT SCHEMATIC
Fig. 61: Brake Switch Circuit Schematic
Courtesy of CHRYSLER LLC
ADDITIONAL WIRING
domingo, 9 de julio de 2023 04:19:43
04:19:38 a. m. Page 1 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article(s).
THEORY OF OPERATION
The brake switch rationality checks both failure modes of the brake switch. The brake switch stuck on test
checks for a high vehicle speed condition where the brake switch is unexpectedly depressed. The brake switch
stuck off test checks for repeated vehicle stop maneuvers without the brake switch depressed.
MONITOR CONDITIONS
When Monitored:
Ignition on.
SET CONDITIONS
Set Condition:
If the output of Brake Switch No. 1 to the PCM looks like it is not applied, while Brake Lamp Switch
Output circuit is applied the fault will mature in 60ms. One Trip Fault.
POSSIBLE CAUSES
Possible Causes
(B15) BRAKE SWITCH NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND
(B16) BRAKE SWITCH NO. 2 SIGNAL CIRCUIT OPEN
(B16) BRAKE SWITCH NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND
(Z904) GROUND CIRCUIT OPEN
STOP LAMP SWITCH
POWERTRAIN CONTROL MODULE (PCM)
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
DIAGNOSTIC TEST
1. ACTIVE DTC
NOTE: Make sure the Stop Lamp Switch is properly adjusted before continuing.
NOTE: Make sure the Stop Lamp Switch is properly wired, such as (B15) Brake
Switch No. 1 and (B16) Brake Switch No. 2 Signal circuit are not switched
at the harness connector.
1. Ignition on, engine not running.
domingo, 9 de julio de 2023 04:19:38 a. m. Page 2 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
2. With a scan tool, select View DTCs.
3. Press and release the Brake Pedal.
Is the DTC Active at this time?
Yes
Go to step 2
No
Refer to the INTERMITTENT CONDITION Diagnostic Procedure. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
2. (B15) BRAKE SWITCH NO. 1 SIGNAL SHORTED TO GROUND
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2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
Fig. 62: Checking Brake Switch No. 1 Signal For A Short
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch harness connector.
3. Disconnect the C3 PCM harness connector.
4. Measure the resistance between ground and the (B15) Brake Switch No. 1 Signal circuit in the Stop
Lamp Switch harness connector.
Is the resistance below 100 ohms?
Yes
Repair the short to ground in the (B15) Brake Switch No. 1 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
No
Go to step 3
3. (B16) BRAKE SWITCH NO. 2 SIGNAL CIRCUIT OPEN
domingo, 9 de julio de 2023 04:19:38 a. m. Page 4 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
Fig. 63: Measuring Resistance Of Brake Switch Signal Circuit
Courtesy of CHRYSLER LLC
1. Disconnect the C3 PCM harness connector.
2. Measure the resistance of the (B16) Brake Switch No. 2 Signal circuit from the Stop Lamp Switch
harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
Go to step 4
No
domingo, 9 de julio de 2023 04:19:38 a. m. Page 5 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
Repair the open in the (B16) Brake Switch No. 2 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
4. (B16) BRAKE SWITCH NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND
Fig. 64: Checking Brake Switch No. 2 Signal For A Short
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (B16) Brake Switch No. 2 Signal circuit in the Stop
Lamp Switch harness connector.
Is the resistance below 100 ohms?
Yes
Repair the short to ground in the (B16) Brake Switch No. 2 Signal circuit.
domingo, 9 de julio de 2023 04:19:38 a. m. Page 6 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
No
Go to step 5
5. (Z904) GROUND CIRCUIT OPEN
Fig. 65: Measuring Resistance Between Ground And Ground Circuit In Stop Lamp Switch Harness
Connector
Courtesy of CHRYSLER LLC
1. Measure the resistance between ground and the (Z904) Ground circuit in the Stop Lamp Switch
harness connector.
Is the resistance below 5.0 ohms?
domingo, 9 de julio de 2023 04:19:38 a. m. Page 7 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
Yes
Go to step 6
No
Repair the open in the (Z904) Ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
6. STOP LAMP SWITCH
1. Measure the resistance between the (Z904) Ground circuit terminal and the (B15) Brake Switch
No. 1 Signal terminal in the Stop Lamp Switch.
2. Next, measure the resistance between the (F942) Fused Ignition Switch Output circuit terminal and
the (B16) Brake Switch No. 2 Signal circuit terminal in the Stop Lamp Switch.
3. Apply and release the Stop Lamp Switch while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to an open circuit for one or both of the
measurements taken?
Yes
Go to step 7
No
Verify that there is good pin to terminal contact in the Switch and Powertrain Control
Module connectors. If OK, replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop
Lamp Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal
contact in the Switch and Powertrain Control Module connectors.
4. Refer to any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
domingo, 9 de julio de 2023 04:19:38 a. m. Page 8 © 2011 Mitchell Repair Information Company, LLC.
2010 Jeep Grand Cherokee Limited
2010 ENGINE PERFORMANCE Powertrain Control Module (PCM) - Electrical Diagnostics - NGC - Grand Cherokee
No
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based
Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
domingo, 9 de julio de 2023 04:19:38 a. m. Page 9 © 2011 Mitchell Repair Information Company, LLC.
