Code deciphering [Archive] - FSB Forums

: Code deciphering


Wedgewood
08-28-2009, 07:22 PM
Okay, after a bit of a delay I finally got the codes. They are as follows:

P0443
P0401
P0402
P1409

Now what?

Just to recap: It's a 1996 Eddie Bauer, 351 with E4OD.

Off- idle stumble when cold.

:banghead

sackman9975
08-28-2009, 07:58 PM
After a google search of those codes, they are all EGR related.

Wedgewood
08-29-2009, 09:17 AM
That's what I cam up as well. Do you think the EGR valve should be straight out replaced or is it worth trying to clean it some how?

miesk5
08-29-2009, 10:01 AM
yo; some info before I have to roll:
DTC P0443 Description & Tests; Finding (& fixing) EVAP system leaks; "...If you can't detect a leak at the moment, record the data, clear the DTC and talk to the customer. There are a number of reasons why the system might not appear to be leaking when you test. Sure, the gas cap might be bad or may have been left loose. The gas tank may be too full to run an accurate test. Some leaks seal up when the temperature increases. You may need to retest the vehicle when it's cold..."
Source: by Ludlow B at motor.com

DTC P0443, P1443, P1444, P1445, P1451; Canister Purge (CANP) solenoid output circuit is checked for opens and shorts internally in the PCM by monitoring the status of the duty-cycled output driver. When the output driver is fully energized, or de-energized, the feedback circuit voltage should respond high or low accordingly (P0443). The Purge Flow Sensor is check for circuit continuity (P1444, P1445) The CANP solenoid functional check uses a Purge Flow Sensor (PFS) to check for adequate purge flow. The PFS voltage is checked when the solenoid valve is normally open (> 75%), then checked when the solenoid valve is commanded closed (0%). Too low a difference between the voltages indicates inadequate canister purge flow or a PFS malfunction (P1443)..." read more
Source: by Ford motorcraftservice.com (http://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM606.pdf)

DTC P0443 & P0443; "...The most common code that will set with these systems is P0443, which has to do with the circuit of the canister purge solenoid or vapor management valve. This code is caused by an electrical problem inside the solenoid, the wiring to it, or a bad PCM. The other common code is a P1443. This is due to the PCM not seeing enough flow through the purge flow sensor when the canister purge solenoid is energized or the IACV not needing to change enough when the VMV is energized..."
Source: by Bob M at asashop.org

DTC P0443: "...Possible Causes: VPWR circuit open, EVAP canister purge valve circuit shorted to GND, Damaged EVAP canister purge valve, EVAP canister purge valve circuit open, EVAP canister purge valve circuit shorted to VPWR, Damaged PCM..."... read more
Source: by bullittarchive.com (http://www.bullittarchive.com/7000/7027/DTC_Codes/P0400_P0499/P0443.htm)
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DTC P0401 & P0402: EGR Flow Insufficient Detected, & EGR Flow Excessive Detected; "...possible causes are a bad DPFE sensor, a bad EGRVR solenoid or possibly a bad PCM. The first thing to check is the wiring for breaks and be sure the connectors are clean and tight. Also check the vacuum lines for proper routing and that there are no breaks or cracks in them..."; MIESK5 NOTE: only 95 5.8L California models & all 96 have the DPFE Sensor instead of EGR Valve Position Sensor (EVP); Ford also calls the DPFE Sensor an EGR Pressure Valve; my 96's Ford pn is F4ZZ9J460-B; new Plastic replacement version is MOTORCRAFT Part #DPFE15
Source: by Matthew W at autorepair.about.com

P1401 - DPF EGR Sensor Circuit High Voltage Detected The EGR monitor checks the DPF EGR sensor signal to the PCM for high voltage. The test fails when the average voltage to the PCM goes to a voltage greater than the maximum calibrated value. DPF EGR circuit open
VREF short to PWR
Damaged DPF EGR sensor (MIESk5 NOTE; CHECK BOTH Hoses;
DPFEGR circuit short to PWR
SIG RTN circuit open
Damaged PCM
A DPF EGR PID reading greater than 4.5 volts with the key ON and engine OFF or running, indicates a hard fault.

DPFE Hose Source & REF Voltage; Source: by miesk5 at FSB (http://fullsizebronco.com/forum/showthread.php?t=146687)
found a local dealer that has each hose for $10.00 (each is 1" long as you described SIG)
They & 3 other dealers in area want $150.00 for the DPFE Sensor though and will not discount; so am getting the MOTORCRAFT DPFE15 thru Amazon w/free S&H for $60.00.

P1409 - EGR Vacuum Regulator Solenoid Circuit Malfunction This test checks the electrical function of the EGRVR solenoid. The test fails when the EGRVR circuit voltage is either too high or too low when compared to the expected voltage range. The EGR system must be enabled for the test to be completed. EGRVR circuit open
VPWR open to EGRVR solenoid
EGRVR circuit short to VPWR or GND
Damaged EGRVR solenoid
Damaged PCM
The EGR vacuum regulator solenoid resistance is from 26 to 40 ohms. (NEED TO VALIDATE THIS IN A BRONCO EVTM/PCED)


DTC P0400 to P0409; "...A common EGR problem with many Fords is a bad DPFE (differential pressure) sensor. The DPFE sensor is part of the EGR system and senses EGR flow when the EGR valve is open. It provides a feedback signal to the engine computer so it can vary EGR flow to meet changing engine loads. The DPFE sensor is usually mounted on the engine and is connected to the pipe that runs from the exhaust manifold to the EGR valve with two rubber hoses. When the sensor goes bad, the Check Engine light comes on and typically sets any or all of teh following fault codes: P0171 & P0174 (lean codes), and/or P0401 (insufficient EGR flow). Nine out of ten times, the fault is not a bad EGR valve or a vacuum leak, but a bad DPFE sensor. A replacement costs about $112 at Ford, or about $48 at an aftermarket auto parts store..." - MIESK5 NOTE: only 95 5.8L California models & all 96 have the DPFE Sensor instead of EGR Valve Position Sensor (EVP) Ford also calls the DPFE Sensor an EGR Pressure Valve - my 96's Ford pn is F4ZZ9J460-B
Source: by Larry C at aa1car.com

DTC PO402, P0401, P1400, & P1401; Usually the failure starts with an almost imperceptible surge while cruising. Gradually it develops into an annoying surge and then the check engine light comes on... Early versions of this part had an aluminum body - this plastic part is an update, and is much less failure prone that the early aluminum part..."...When OBD2 came along, the EPA said that we now have to be able to know if the EGR valve quits working and turn the check engine light on if it does. Ford chose to do this by installing a slight restriction in the tube that brings exhaust to the EGR valve. Now we all know from science class that when there is flow through an orfice, there is a pressure drop across it. So Ford installed a pressure sensor across the orfice - when there is flow because the EGR valve opened, the pressure sensor senses the flow and tells the PCM the system is working. That's why they call it a Differential Pressure Feedback EGR Sensor! Now, what do you think happens when you run hot exhaust gas into a little electronic sensor? It does not last too long.."

Maybe someone else can add more and better info from a BRONCO EVTM/PCED
Suggest you buy a Ford Bronco Electrical and Vacuum Troubleshooting Manual (EVTM) - Powertrain Controls and Emission Diagnosis Manual (PCED) EVTM/PCED CD or DVD - best $10.00 you'll ever spend.

miesk5
08-31-2009, 10:47 AM
Well?