| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. | 
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. | 
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. | 
Circuit  | Short to Ground  | High Resistance  | Open  | Short to Voltage  | Signal Performance  | 
|---|---|---|---|---|---|
APP Sensor 2 - 5-Volt Reference  | P0117, P0462, P0522, P0652, P011A, P2454  | P2138  | P2127  | P0118, P0653, P011A, P244B, P2455  | --  | 
Oil Pressure Sensor - 5-Volt Reference  | P0117, P0462, P0522, P0652, P011A, P2454  | P0522  | P0522  | P0118, P0522, P0653, P011A, P244B, P2455  | --  | 
Fuel Rail Pressure Sensor - 5-Volt Reference  | P0117, P0462, P0522, P0652, P011A, P2454  | P0087, P0192  | P0193  | P0118, P0653, P011A, P2455  | --  | 
DPF Differential Pressure Sensor  | P0117, P0462, P0652, P011A P2454  | P2453, P244B  | P2454  | P0118, P0653, P011A P2455  | --  | 
The engine control module (ECM) supplies 5 volts to components through 5-volt reference circuits. These 5-volt reference circuits are independent of each other outside the ECM, but are bussed together in three reference groups inside the ECM. Therefore, a circuit condition on one sensor 5-volt reference circuit may affect multiple components. The ECM monitors voltage on the 5-volt reference circuits.
| • | The ignition is ON. | 
| • | The diagnostics run continuously. | 
| • | The ECM detects the 5-volt reference 2 circuit voltage is less than 4.7 volts. | 
| • | The above condition is present for 2 seconds. | 
| • | The ECM detects the 5-volt reference 2 circuit voltage is more than 5.2 volts. | 
| • | The above condition is present for 2 seconds. | 
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. | 
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. | 
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. | 
| • | 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 emission related diagnostic. | 
| • | Clear the MIL and the DTC with a scan tool. | 
| • | The engine starts and runs. | 
| • | Observe the 5-Volt Reference 2 Circuit Status parameter with a scan tool. The parameter should display OK. | 
Important: Additional DTCs will set when disconnecting the components.
Important: A short to voltage on the signal circuit of certain components may cause this DTC to set.
| ⇒ | If the voltage is less than the specified range, test for a short to ground on all the 5-volt reference circuits. If all circuits test normal, replace the ECM. | 
| ⇒ | If the voltage is greater than the specified range, test for a short to voltage on all the 5-volt reference circuits. If all circuits test normal, replace the ECM. | 
| ⇒ | If the voltage display increases greater than the specified value when a component is connected, test the signal circuit for a short to voltage. If all circuits test normal, replace the ECM. | 
| ⇒ | If the voltage display decreases more than the specified value when a component is connected, replace the component. | 
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |