Engine Codes P0472 and P0475 - Diesel Forum - TheDieselStop.com
'99 & up 7.3L Power Stroke Engine and Drivetrain Discussion of the '99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

 
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post #1 of 2 (permalink) Old 03-09-2010, 03:43 PM Thread Starter
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Unhappy Engine Codes P0472 and P0475

Hi, my engine is throwing codes P0472 and P0475. I did a little research on the forums and discovered that the P0472 is the exhaust back pressure sensor malfunctioning and the P0475 is the exhaust valve malfunctioning. It appeared that most people where getting these codes due to engine mods. I bought mine used and the previous person did some modifications but I have no clue what was done and my experience with Diesel is limited. How can I tell if these are resulting from modifications and should be ignored or if they are a real issue? My wife recently ran it out of Diesel and I tried to start it for a total of maybe 30 min before I finally gave in and bled the lines. Could this have caused these codes? What would happen if I just ignore the codes? Any suggestions would be greatly appreciated! Thanks!
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post #2 of 2 (permalink) Old 03-09-2010, 04:08 PM
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For P0472, Check to see if your EBP sensor has been disconnected.

Engine Codes P0472 and P0475-28333ebp_sensor_1.jpg
If not, then follow the troubleshooting steps here. Hopefully you won't have to go too far down the list.

DTC P0472 indicates EBP sensor circuit low input was detected during KOEO Self Test or during continuous diagnostic monitoring.
  • Possible causes:
  • open EBP sensor circuit
  • biased sensor/PCM
  • short to SIGN RTN or PWR GND on EBP sensor circuit
  • open in VREF circuit
Disconnect EBP sensor harness connector.
Key on, engine off.
Measure voltage between Pin B Circuit 351 (BR/W) on harness connector and battery ground.
Key off.
Was voltage reading 5 V ± 0.5?
Yes - GO to «DE10».
No - REPAIR open in VREF Circuit 351 (BR/W). RESTORE vehicle. CLEAR DTCs and RETEST.

DE10 SIG RTN CIRCUIT CHECK
Measure resistance between Pin A Circuit 359 (GY/R) and ground.
Is resistance less than 5 ohms?
Yes - GO to «DE11».
No - REPAIR open in SIG RTN Circuit 359 (GY/R). RESTORE vehicle. CLEAR DTCs and RETEST.

DE11 EBP SIGNAL CIRCUIT CHECK
Install breakout box; leave PCM disconnected.
Measure resistance between PCM Test Pin 30 and Pin C Circuit 553 (P/LB) at EBP sensor harness connector.
Is resistance less than 5 ohms?
Yes - GO to «DE12».
No - REPAIR open in EBP signal wire Circuit 553 (P/LB). RESTORE vehicle. CLEAR DTCs and RETEST.

DE12 VREF CIRCUIT CHECK
Measure resistance between PCM Test Pin 90 and Pin B Circuit 351 (BR/W) at EBP sensor harness connector.
Is resistance less than 5 ohms?
Yes - GO to «DE13».
No - REPAIR open in EBP VREF (Circuit 351 [BR/W]). RESTORE vehicle. CLEAR codes and RETEST.

DE13 GROUNDED EBP SIGNAL CIRCUIT CHECK
Measure resistance between PCM Test Pin 30 and PCM Test Pins 25, 91, 51, 76, 77 and 103.
Is resistance greater than 10,000 ohms?
Yes - GO to «DE14».
No - REPAIR short to ground in EBP signal wire Circuit 533 (P/LB). RESTORE vehicle. CLEAR DTCs and RETEST.

DE14 CHECK FOR INTERNAL PCM SHORT ON PIN 30
Connect PCM to breakout box.
Measure resistance between PCM Test Pin 30 and PCM Test Pins 25, 91, 51, 76, 77 and 103.
Is resistance greater than 10,000 ohms?
Yes - REPLACE EBP sensor. RESTORE vehicle. CLEAR DTCs and RETEST.
No - REPLACE PCM. RESTORE vehicle. CLEAR DTCs and RETEST.

For P1475, check to see if your EPR connection has been unplugged (located on the front of the turbo pedestal below the turbo.) If not, then follow these troubleshooting steps:

KB1 DIAGNOSTIC TROUBLE CODE (DTC) P0475
possible causes:
  • shorted to power
  • open/grounded circuit
  • damaged solenoid
  • damaged PCM
Disconnect EPR harness connector.
Measure resistance between Pin A and ground.
Is the resistance less than 5 ohms?
Yes - GO to «KB2».
No - REPAIR open in Circuit 570 (BK/W). RESTORE system. CLEAR DTCs and RETEST.

KB2 CHECK EPR COIL
Measure resistance across EPR coil contacts A and B.
Is the coil resistance between 2.5 ohms and 12 ohms?
Yes - GO to «KB3».
No - REPLACE regulator. RESTORE system. CLEAR DTCs and RETEST.
KB3 CHECK FOR SHORT TO POWER IN CIRCUIT 318 (GY/R).
Disconnect PCM harness connector.
Measure voltage between Pin B and ground.
Shake harness.
Is B+ ever present?
Yes - REPAIR short to power in Circuit 318 (GY/R). RESTORE system. CLEAR DTCs and RETEST.
No - GO to «KB4».

KB4 CHECK CIRCUIT 318 (GY/R) FOR SHORT TO GROUND
Measure resistance between Pin B and ground.
Shake harness.
Does the resistance ever drop below 10,000 ohms?
Yes - REPAIR short to ground in Circuit 318 (GY/R). RESTORE system. CLEAR DTCs and RETEST.
No - GO to «KB5».

KB5 CHECK FOR OPEN IN CIRCUIT 318 (GY/R)
Install breakout box; leave PCM disconnected.
Measure resistance between Pin B and Test Pin 42.
Shake harness.
Does resistance ever go above 5 ohms?
Yes - REPAIR open in Circuit 318 (GY/R). RESTORE system. CLEAR DTCs and RETEST.
No - GO to «KB6».

KB6 PERFORM OUTPUT STATE CHECK
Key on, engine off.
Measure voltage between EBP connector harness side Pin B and chassis ground.
Run KOEO Output State Self Test on NGS Tester.
Does voltage toggle between 12 V and 0 V?
Yes - Fault is intermittent; unable to duplicate failure. RESTORE system. CLEAR DTCs and RETEST.
No - REPLACE PCM. RESTORE system. CLEAR DTCs and RETEST.

You can ignore the codes as they aren't a critical function unless your EBPV is staying closed. Neither of these should cause the SES light to come on normally, but it might after a couple of drive cycles. From the service manual "MIL (OBDII) illuminates after second consecutive fault."

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99.5 F250 PSD Supercab LB 4x4, ZF-6 w/SB Con OFE, 3.73LS, Boost & pyro gauges, Swamps S175/146 injectors, DP 80 HP Econo PCM (classic version), AIS, coolant filter w/"hokum" bracket, regulated return, heated mirror mod, lighted cupholder, Marinco heater plug-in.

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Last edited by klhansen; 03-09-2010 at 04:11 PM.
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