Diagnostic Test

WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

DTC IS ACTIVE
1. Start the engine and allow it to reach normal operating temperature.
  WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.
  
  NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.
2. With the scan tool, select View DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go to step 2
  No
  - Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(F856) 5-VOLT SUPPLY CIRCUIT VOLTAGE

Fig 1: Checking EGR Sensor 5-Volt Supply Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Exhaust Gas Recirculation Valve connector.
3. Turn the ignition on.
4. Measure the voltage of the (F856) 5-volt Supply circuit in the Exhaust Gas Recirculation Valve harness connector.
  Is the voltage above 4.5 volts?
  
  Yes
  - Go to step 6
  No
  - Go to step 3
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Fig 2: Checking 5-Volt Supply Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition on.
2. Disconnect the Powertrain Control Module (PCM) C1 and C2 harness connectors.
3. Measure the resistance between ground and the (F856) 5-volt Supply circuit in the Exhaust Gas Recirculation Valve harness connector.
  Is the resistance above 100 Ohms?
  
  Yes
  - Go to step 4
  No
  - Repair the (F856) 5-volt Supply circuit for a short to ground.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K900) SENSOR GROUND CIRCUIT

Fig 3: CHECKING EGR SENSOR 5-VOLT CIRCUIT FOR SHORT TO SENSOR GROUND CIRCUIT
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (F856) 5-volt Supply circuit and the (K900) Sensor Ground circuit in the Exhaust Gas Recirculation Valve harness connector.
  Is the resistance above 100 Ohms?
  
  Yes
  - Go to step 5
  No
  - Repair the (F856) 5-volt Supply circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(F856) 5-VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Fig 4: CHECKING EGR SENSOR 5-VOLT SUPPLY CIRCUIT FOR OPEN OR HIGH RESISTANCE
Courtesy of CHRYSLER LLC

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install the PCM Pinout Box 8815 to perform diagnosis.
1. Measure the resistance of the (F856) 5-volt Supply circuit between the Exhaust Gas Recirculation Valve harness connector and the appropriate terminal of PCM Pinout Box 8815.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 10
  No
  - Repair the (F856) 5-volt Supply circuit for an open circuit or high resistance.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K34) EGR SIGNAL CIRCUIT SHORTED TO GROUND

Fig 5: CHECKING EGR SIGNAL CIRCUIT FOR SHORT TO GROUND
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) C2 harness connector.
3. Measure the resistance between ground and the (K34) EGR Signal circuit in the Exhaust Gas Recirculation Valve harness connector.
  Is the resistance above 100 Ohms?
  
  Yes
  - Go to step 7
  No
  - Repair the (K34) EGR Signal circuit for a short to ground.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K34) EGR SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Fig 6: CHECKING EGR SIGNAL CIRCUIT FOR SHORT TO SENSOR GROUND CIRCUIT
Courtesy of CHRYSLER LLC
1. Measure the resistance between the (K34) EGR Signal circuit and the (K900) Sensor Ground circuit in the Exhaust Gas Recirculation Valve harness connector.
  Is the resistance above 100 Ohms?
  
  Yes
  - Go to step 8
  No
  - Repair the (K34) EGR Signal circuit for a short to the (K900) Sensor Ground circuit.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
(K34) EGR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Fig 7: CHECKING EGR SIGNAL CIRCUIT FOR OPEN OR HIGH RESISTANCE
Courtesy of CHRYSLER LLC

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install the PCM Pinout Box 8815 to perform diagnosis.
1. Measure the resistance of the (K34) EGR Signal circuit between the Exhaust Gas Recirculation Valve harness connector and the appropriate terminal of PCM Pinout Box 8815.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go to step 9
  No
  - Repair the (K34) EGR Signal circuit for an open circuit or high resistance.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
EXHAUST GAS RECIRCULATION VALVE
1. Turn the ignition off.
2. Connect the Powertrain Control Module (PCM) C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, read the Exhaust Gas Recirculation Valve signal voltage.
  NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.
  
  Does the scan tool display the voltage as described above?
  
  Yes
  - Replace the Exhaust Gas Recirculation Valve in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Go to step 10
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Exhaust Gas Recirculation Valve 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.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Refer to any Technical Service Bulletins (TSBs) that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
  - Perform the PCM VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure .