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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5571
Experience:  Owner at DJ Wilson
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Beaver monterey, cummins I sc 350 hp, low fuel pressure code

Customer Question

beaver monterey, cummins I sc 350 hp, low fuel pressure code (engine warning light (EWL)).
Freightliner shop (Delta Truck Center at French Camp, CA) south of Stocton Ca spent 2 days.
Pressure and vacuum gauges on lift pump checked OK.
Checked wiring harness at accumulator PSI plug. White wire (fuel sensor?) fell out of connector as connector was removed from pressure sensor and was repaired.
Ran smooth in shop with no EWL. Test drive brought EWL at beginning of drive then none in 20 miles. Stop then full throttle five times caused one EWL.
Replaced fuel pressure sensor thinking that it might be sticking. l Road test produced a couple of EWL.
Coach has a "translator box wired into fuel PSI circuit. Unplugged box and it generated three other codes, 123, 452, 268. checked pins and OK.
Road test 20 miles monitoring fuel PSI vs voltage of pump.No codes.
returned to customer (me).
The above is a summary of the shop actions.
During the return to home , near Seattle, continued to get EWL and observed two things.
1. EWL seemed to only occur when outside temperature is low (70 deg or lower).
2. and the engine was running between 45 and 65 percent load as displayed on the "Aladin" monitoring system.
Thanks *****
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 year ago.

Hi AJ, My name is***** with me while I Pull up those codes.

Expert:  Daniel Wilson replied 1 year ago.

123 Intake Manifold Pressure Sensor Circuit

268 Fuel Pressure Sensor Circuit

Possible causes:

-ECM software updates needed

-Faulty pressure sensor or harness

-Poor ECM grounds

452 Fuel Pressure Sensor Circuit

Low voltage at the pressure/temperature sensor . check connector pin 46 for corrosion or poor connections at the rear of the accumulator.

Expert:  Daniel Wilson replied 1 year ago.

123 is low voltage detected at signal pin 45 from the ECM for the boost pressure sensor. Check the ECM power and grounds and verify the ECM has sufficient power and ground and the batteries and charging system test good as well as all connections between the batteries and starter. Let me know