0334770 JOHNSON BASE, Air silencer

The following conditions must exist before any of the above codes will become active:
There are no active 3509 codes.
There are no active 168 codes.The following background information is related to this procedure:The 5 VDC sensor supply provides power to all 5 VDC sensors. The sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM.Pull-up VoltageThe ECM continuously outputs a pull-up voltage on the circuit for the sensor signal wire. The ECM uses this pull-up voltage to detect an open in the signal circuit. When the ECM detects a voltage above a threshold on the signal circuit, an open circuit diagnostic code (XXXX-3) is generated for the sensor.If the sensor is disconnected, pull-up voltage indicates that the wires from the sensor connector to the ECM are not open or shorted to ground. If the sensor is disconnected, the absence of pull-up voltage indicates an open in the signal wire or a short to ground. If the sensor is disconnected and the voltage is different from pull-up voltage, the signal wire is shorted to another wire in the harness.
Illustration 1 g06457878
Schematic diagram for the active sensors
Table 2
Troubleshooting Test Steps Values Results
1. Download Information Using the Electronic Service Tool
A. Use the electronic service tool to download the "Product Status Report" (PSR) with histograms before performing any troubleshooting or clearing any diagnostic codes.
Note: The downloaded information will be required by the Dealer Solutions Network (DSN) if troubleshooting assistance is required.
Downloaded information
Result: The information was successfully saved.
Proceed to Test Step 2.
Result: The electronic service tool information was not successfully saved.
Contact the Dealer Solutions Network (DSN) for guidance.
2. Create an Electronic Service Tool Snapshot (only applicable to 157–3 and 157–4 diagnostic codes)
A. Select "Snapshot Viewer" on the electronic service tool, using menus: Information -> Snapshot -> Viewer
B. Select the event code and then click "View Graph".
C. Select the following parameter and then click OK.
Engine Speed
D. Select Save to "File to save" a Snapshot File (*.xml). This file will contain all the data in the snapshot and not only the data shown on the graph.
Note: The downloaded information will be required by the DSN if troubleshooting assistance is required.
Snapshot saved
Result: The electronic service tool snapshot was successfully saved.
Proceed to Test Step 3.
Result: The electronic service tool snapshot was not successfully saved.
Contact the DSN for guidance.
3. Check for Diagnostic Codes
A. Establish communication between the electronic service tool and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Turn the keyswitch to the ON position.
C. Look for active or logged diagnostic codes for the active sensors.
Diagnostic code
Result: There are no active diagnostic codes for the active sensors.
Repair: If there are logged diagnostic codes for the active sensors, the fault may be intermittent.
Refer to Troubleshooting, "Electrical Connectors - Inspect" to identify intermittent faults.
Result: A diagnostic code that is listed in Table 1 is active.
Proceed to Test Step 4.
4. Check the 5 VDC Supply Voltage at the Sensor Connector
A. Turn the keyswitch to the ON position.
B. Measure the voltage between the sensor supply pin and the sensor return pin at the suspect sensor.
Test passed
Result: The supply voltage is approximately 5.0 0.2 VDC
Connect the sensor and then proceed to Test Step 5.
Result: The supply voltage is not approximately 5.0 0.2 VDC.
The fault is in the 5 V supply wiring to the suspect sensor. Repair the wiring or replace the harness
Verify that the problem is resolved.
5. Check the Type of Diagnostic Code that is Active
A. Turn the keyswitch to the ON position. Wait at least 10 seconds for activation of the diagnostic codes.
B. Use the electronic service tool to check for active diagnostic codes. Record all active diagnostic codes.
Diagnostic codes Result: A 157-12 diagnostic code is active.
Repair: Replace the fuel rail pressure sensor.
Note: Do not replace the fuel rail pressure sensor if the 157-12 diagnostic code is logged. Only replace the sensor for an active 157-12 diagnostic code.
Use the electronic service tool to clear all logged diagnostic codes. Return the unit to service.
If the fault is still present, contact the Dealer Solutions Network (DSN).
Result: A 108-12 diagnostic code is active.
Repair: Install a replacement ECM.
Use the electronic serv