Diagnostic Test

WARNING: This page is about a different car, the 2016 Jeep Wrangler and 2015 Jeep Wrangler. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR AN ACTIVE DTC
NOTE:
If DTC P258A is active, perform the diagnostic procedure for P258A before continuing with this test procedure.

NOTE:
Diagnose and repair any Vacuum Pressure Sensor DTCs that are present in the PCM or ABS Module before continuing with this test procedure.
1. Start the engine and allow it to idle.
2. Press and release the Brake Pedal several times to cause the EVP to operate.
3. With the scan tool, read DTCs.
  Is the DTC active or pending?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to .
ELECTRIC VACUUM PUMP ACTUATION
1. Turn the ignition on, engine not running.
2. With the scan tool actuate the Electronic Vacuum Pump.
  Does the Electric Vacuum Pump run?
  
  Yes
  - Go To 8
  No
  - Go To 3
CHECK THE (T109) ELECTRIC VACUUM PUMP OUTPUT CIRCUIT
1. Disconnect the EVP harness connector.
2. With the scan tool actuate the Electronic Vacuum Pump.
3. Using a 12-volt test light connected to ground, probe the (T109) Electric Vacuum Pump Output circuit at the Electric Vacuum Pump harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Go To 5
CHECK THE EVP GROUND CIRCUIT
1. Using a 12-volt test light connected to 12 volts, probe the EVP Ground circuit at the Electric Vacuum Pump harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Replace the Electric Vacuum Pump in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Repair the EVP Ground circuit for an open.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK THE (T109) ELECTRIC VACUUM PUMP OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Remove the EVP Relay from the relay connector in the Auxiliary PDC.
3. Measure the resistance of the (T109) Electric Vacuum Pump Output circuit between the EVP Relay connector and the EVP harness connector.
  Is the resistance below 3.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (T109) Electric Vacuum Pump Output circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK THE (T109) ELECTRIC VACUUM PUMP OUTPUT CIRCUIT FOR A SHORT TO GROUND
1. Check for continuity between ground and the (T109) Electric Vacuum Pump Output circuit at the EVP Relay connector.
  Is there continuity between ground and the (T109) Electric Vacuum Pump Output circuit?
  
  Yes
  - Repair the (T109) Electric Vacuum Pump Output circuit for a short to ground. If the circuit was shorted to ground, test the Fuse in the Auxiliary PDC and replace if necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Go To
CHECK THE (A206) FUSED B+ CIRCUIT AT THE EVP RELAY
1. Turn the ignition on.
2. Using a 12-volt test light connected to ground, probe the (A206) Fused B+ circuit at the EVP Relay connector (terminal 30).
  Does the test light illuminate brightly?
  
  Yes
  - Replace the Vacuum Pump Relay. With the scan tool actuate the Electronic Vacuum Pump. Using a 12-volt test light connected to ground, probe the (T109) Electric Vacuum Pump Output circuit at the Electric Vacuum Pump harness connector. If the test light still does not illuminate brightly, replace the Front PDC in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Repair the (A206) Fused B+ circuit for an open or short to ground. If no problems are found with the (A206) Fused B+ circuit and the fuse is not blown, replace the TIPM in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK THE VACUUM SUPPLY LINE
1. Turn the ignition off.
2. Check the vacuum supply line to brake booster for a pinched, cut or open hose.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Go To 9
VACUUM PRESSURE SIGNAL
1. Start the engine.
2. With the scan tool, view and record the vacuum pressure signal with foot off the brake pedal.
3. With the scan tool, view the vacuum pressure signal while pressing the brake pedal several times.
4. Record the highest value.
  Without the brake pedal applied, was the vacuum pressure signal -40 kPa (-12 in Hg)?
  
  Yes
  - Go To 10
  No
  - Replace the Brake Booster in accordance with the Service Information. Refer to BOOSTER, POWER BRAKE , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK FOR VACUUM PRESSURE SIGNAL CHANGE
1. Turn the ignition on.
2. Remove the Vacuum Pressure Sensor from the Brake Booster.
3. Connect a vacuum pump to the Vacuum Pressure Sensor.
4. Apply vacuum to the Vacuum Pressure Sensor and watch for signal change.
  Is the voltage signal changing on the scan tool as vacuum is being applied?
  
  Yes
  - Go To 11
  No
  - Replace the Vacuum Pressure Sensor in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK BRAKE BOOSTER CHECK VALVE
1. Remove the Brake Booster Check Valve.
2. Apply vacuum to the booster side of the check valve.
  Is the Brake Booster Check Valve holding vacuum?
  
  Yes
  - Go To 12
  No
  - Replace the Brake Booster Check Valve in accordance with the Service Information. Refer to BOOSTER, POWER BRAKE , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK BRAKE BOOSTER
1. Reinstall the Brake Booster Check Valve.
2. Apply vacuum to the Brake Booster.
  Is the Brake Booster holding vacuum?
  
  Yes
  - Go To 13
  No
  - Replace the Brake Booster in accordance with the Service Information. Refer to BOOSTER, POWER BRAKE , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Powertrain Control Module in accordance with the Service information. Refer to MODULE, POWERTRAIN CONTROL [EHD,ERB] , REMOVAL MODULE, POWERTRAIN CONTROL, 2.8L DIESEL [ENS] , REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  No
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to .
  - Test complete.