RENR5042-02 129 Troubleshooting Section Verify that the repairs eliminate the problem. Atmospheric pressure sensor STOP. This procedure covers the following diagnostic codes: Test Step 3. Check the Batteries 094-03Fuel Pressure open/short to +batt A. Measure the no-load battery voltage at the battery posts. 094-04Fuel Pressure short to ground 100-03 Engine Oil Pressure open/short to +batt B. Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, “Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries” and Special Instruction, SEHS7633, “Battery Test Procedure”.
100-04 Engine Oil Pressure short to ground 102-03 Boost Pressure Sensor short to +batt 102-04 Boost Pressure Sensor short to ground Expected Result: 274-03 Atmospheric Pressure open/short to +batt The batteries pass the load test. The measured voltage is the minimum specification for a 12V or 24V system. 274-04 Atmospheric Pressure short to ground The troubleshooting procedures for the diagnostic codes of each pressure sensor are identical. The Engine Control Module (ECM) sends a 5 volt supply to terminal A of each sensor. The sensor common connection is connected to terminal B of each sensor.
The signal voltage from terminal C of each sensor is sent to the appropriate terminal at the J2/P2 ECM connector. Results: OK The batteries are OK. Repair: Check the wiring between the batteries and the ECM for shorts. Check the connectors between the batteries and the ECM for moisture and/or corrosion. Pull-up Voltage The ECM continuously outputs a pull-up voltage on the circuit for the sensor signal wire. The ECM uses this pull-up voltage in order to detect an open in the signal circuit. When the ECM detects the presence of a voltage that is above a threshold on the signal circuit, the ECM will generate an open circuit diagnostic code (03) for the sensor.
Repair the wiring and/or the connectors. Verify that the repair eliminates the problem. STOP. Not OK – The battery voltage is low or the battery did not pass the load test. If the sensor is disconnected at the sensor connector, the presence of pull-up voltage at the sensor connector indicates that the wires from the sensor connector to the ECM are not open or shorted to ground. If the sensor is disconnected at the sensor connector, the absence of pull-up voltage at the sensor connector indicates an open in the signal wire or a short to ground.
If the sensor is disconnected at the sensor connector and the voltage at the sensor connector is different from pull-up voltage, the signal wire is shorted to another wire in the harness. Repair: Recharge or replace the faulty batteries. Verify that the repair eliminates the problem. STOP. i02289985 Engine Pressure Sensor Open or Short Circuit - Test SMCS Code: 5574-038-PX System Operation Description: Use this procedure to troubleshoot any suspect problems with the following sensors: Engine oil pressure sensor Boost pressure sensor