1996 PCED OBDI
SECTION 18: Diesel Diagnosis — 7.3L DI Engine

M: Exhaust Back Pressure Regulator (EPR)
  M: Introduction  

 

M1 DIAGNOSTIC TROUBLE CODE (DTC) 0475: CHECK FOR GROUND IN CIRCUIT 574 (BK/PK). DTC 0475 INDICATES THAT A CIRCUIT FAILURE HAS OCCURRED IN THE EBP CONTROL SOLENOID CIRCUIT

Is the resistance less than 5 ohms?
YesNo
GO to M2.SERVICE open in Circuit 574 (BK/PK). RERUN Scan Tool Diagnostic Test.
 

M2 CHECK EPR COIL

Is the coil resistance between 2.5 ohms and 12 ohms?
YesNo
GO to M3.REPLACE regulator. RERUN Scan Tool Diagnostic Test.
 

M3 CHECK FOR SHORT TO POWER IN CIRCUIT 318 (GY/R).

Is B+ present?
YesNo
SERVICE short to power in Circuit 318 (GY/R). RERUN Scan Tool Diagnostic Test.GO to M4.
 

M4 CHECK CIRCUIT 318 (GY/R) FOR SHORT TO GROUND

Is the resistance greater than 10,000 ohms?
YesNo
GO to M5.SERVICE short to ground in Circuit 318 (GY/R). RERUN Scan Tool Diagnostic Test.
 

M5 PERFORM OUTPUT STATE CHECK

Does voltage toggle between 12v and 0v?
YesNo
REASSEMBLE system. RERUN standard KOEO and KOER tests. If codes still present, REPLACE PCM.GO to M6.
 

M6 CHECK FOR OPEN IN CIRCUIT 318 (GY/R)

Is resistance less than 5 ohms?
YesNo
REASSEMBLE system. RERUN standard KOEO and KOER tests. If codes still present, REPLACE PCM.SERVICE open in Circuit 318 (GY/R). RERUN Scan Tool Diagnostic Test.
 

M7 KOER DIAGNOSTIC TROUBLE CODE (DTC) 0476

Is tang in the open position?
YesNo
GO to M8.REPAIR condition causing valve to be stuck closed.
 

M8 EXHAUST RESTRICTION CHECK

Is EBP below 28 psi?
YesNo
GO to M9.REPAIR restricted exhaust condition. CLEAR DTC and RETEST.
 

M9 EBP SENSOR CHECK

Does EBP increase at least 4 psi with acceleration?
YesNo
M10.REPLACE EBP sensor. RETEST system.
 

M10 INSPECT FOR EXHAUST LEAKS

Are exhaust leaks present?
YesNo
REPAIR exhaust leak. CLEAR DTCs and RETEST.GO to M11.
 

M11 EBP CHECK DURING KOER

Does voltage increase 2.0v ± .5 and then decrease as the test ends?
YesNo
REPLACE PCM. CLEAR DTCs and RETEST.GO to M12.
 

M12 EPR VISUAL INSPECTION

Does the linkage move during the test?
YesNo
CHECK EPR linkage adjustment. REFER to Section 03-04E of the Powertrain, Drivetrain Service Manual for adjustment procedure. RETEST system.REPLACE EPR valve. CLEAR DTCs and RETEST.