Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSJEEP2009WRANGLER SAHARA, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)BRAKESANTI-LOCK BRAKESANTI-LOCK BRAKE SYSTEM - ELECTRICAL DIAGNOSTICSDTC TROUBLESHOOTINGC1008-BRAKE FLUID LEVEL CIRCUIT HIGHDIAGNOSTIC TEST

2009 Jeep Wrangler Sahara, Standard

Diagnostic Test

2009 Jeep Wrangler Sahara, StandardSECTION Diagnostic Test

CHECK FOR ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. Using the scan tool, read the TIPM DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go to step 2
  No
  - Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

Fig 1: Checking Brake Fluid Level Signal Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Brake Fluid Level Switch harness connector.
3. Disconnect the TIPM C7 harness connector.
4. Turn the ignition on.
5. Measure the voltage between ground and the (B20) Brake Fluid Level Signal circuit.
  Is there any voltage present?
  
  Yes
  - Repair the short to voltage in the (B20) Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .
  No
  - Go to step 3
CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR AN OPEN

Fig 2: Checking Brake Fluid Level Signal Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance of the (B20) Brake Fluid Level Signal circuit between the Brake Fluid Level Sensor harness connector and the TIPM C7 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 4
  No
  - Repair the open in the (B20) Brake Fluid Level Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .
CHECK THE (K91) SENSOR GROUND CIRCUIT FOR AN OPEN

Fig 3: Checking Sensor Ground Circuit
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (K91) Sensor Ground circuit between the Brake Fluid Level Sensor harness connector and the TIPM C7 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 5
  No
  - Repair the open in the (K91) Sensor Ground circuit.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .
BRAKE FLUID LEVEL SWITCH INTERNAL FAILURE

Fig 4: Brake Fluid Level Switch Circuit
Courtesy of CHRYSLER LLC
1. Reconnect the TIPM C7 harness connector.
2. Connect a jumper wire between the (B20) Brake Fluid Level Signal circuit and the (K91) Sensor Ground circuit in the Brake Fluid Level Sensor harness connector.
3. Turn the ignition on.
4. Using the scan tool, read the Brake Fluid Level voltage
  Is the voltage below 1.0 Volt?
  
  Yes
  - Replace the Brake Fluid Level Sensor in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .
  No
  - Replace the TIPM in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.