DDEC III/IV Single ECM Troubleshooting – Section 48.3 Troubleshooting Flash Code 48

Section 48.3
Troubleshooting Flash Code 48

Fuel Pressure code is logged as a result of a mechanical fault. Check for reasons for low fuel pressure. Refer to appropriate service manual, section 5. ‪

This (Gas-fueled engine) code is logged as a result of a mechanical fault. Check for reasons for low air inlet pressure. Refer to appropriate service manual, section 6. ‪

For all EGR related codes, always perform the basic checks in (EGR-1) for Series 50 engines; refer to "10.16 Exhaust Gas Recirculation System (EGR-1) – Fault, Series 50 Engine" . For Series 60 engines, refer to "10.18 Exhaust Gas Recirculation System Basic Checks for Series 60 Engines" .‪

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Then, perform the following steps to troubleshoot code 48: ‪

Section 48.3.1
Check for Other Codes

Perform the following steps to check for other codes:‪

1. Turn ignition ON.
2. Plug in DT.
3. Read active codes.
   1. If codes 63 (s 060) and/or 31 (s 52) display, service those codes first.
   2. If codes 63 (s 060) and/or 31 (s 52) do not display, refer to "48.3.2 Vehicle Air Test" .

Section 48.3.2
Vehicle Air Test

Perform the following steps to check the vehicle air test. The vehicle air test should have been performed during EGR–1 on a Series 50 engine; refer to "10.16 Exhaust Gas Recirculation System (EGR-1) – Fault, Series 50 Engine" . On a Series 60 engine, refer to "10.18 Exhaust Gas Recirculation System Basic Checks for Series 60 Engines" . If the test was not performed, refer to proper section and perform all steps.‪

1. If the vehicle air system failed the test, resolve low vehicle air pressure.
2. If the vehicle air system passed the test, replace the EGR valve and refer to "48.3.3 Verify Repairs" for verification of repairs.
3. No additional DDEC troubleshooting is recommended for these six codes. Check all Basic Checks and then contact Technical Service for instructions, providing a snapshot and code logging details.

Section 48.3.3
Verify Repairs

Perform these steps to verify repairs to the vehicle air system: ‪

1. Connect all connectors.
2. Start engine.
3. Perform road test.
4. Has the fault returned?
   1. If the code is logged, review this section to find the error. If the fault returns after review, try a test ECM or contact Detroit Diesel Technical Services.
   2. If no codes are logged, troubleshooting is complete.