97 F150, 4.2L V6 200k miles

Truck has been running fine. No CEL, or anything. Stopped and filled up the tank and within 10 minutes of leaving the pump, the CEL came on. Code is P0430.

I drive this truck 60 miles a day. It's shown no signs of any issues until the light came on today. Just curious if some bad gas could cause this or am I in for CAT replacement...

Thanks.

 

P0403 - Exhaust Gas Recirculation Circuit Malfunction

OBD-II Trouble Code Technical Description

Exhaust Gas Recirculation Circuit Malfunction

What does that mean?

The Exhaust Gas Recirculation (EGR) system is controlled by a vacuum solenoid. The solenoid is supplied ignition voltage. The Powertrain Control Module (PCM) controls the vacuum solenoid by grounding the control circuit(ground) or driver




The primary function of the driver is to supply ground for the object that is being controlled. Each driver has a fault circuit that the PCM monitors. When the PCM turns a component on, the control circuit voltage is low, or close to zero. When the component is turned off, the voltage on the control circuit is high, or near battery voltage. The PCM watches for these conditions, and if it doesn\'t see the proper voltage at the proper time, this code is set.

Potential Symptoms

Usually a fault in the control circuit, will leave no noticeable symptoms other than the Malfunction Indicator Lamp (MIL) illumination. However, if the EGR control solenoid is stuck open due to debris, etc. the code may be accompanied by misfire under acceleration, rough idle, or engine dying altogether.

Causes

The causes for a P0403 EGR code could be any of the following:
•Bad EGR solenoid
•Excessive resistance in control circuit (PCM controlled ground) due to an open, chafing or damage to the harness
•Poor connection at the EGR solenoid harness (worn or loose pins)
• Water intrusion at the EGR solenoid harness
• Blockage in EGR control solenoid holding solenoid open or closed causing excessive resistance
• Loss of supply voltage to EGR solenoid
• Bad PCM

Possible Solutions

With the ignition on and engine off, use a scan tool to activate the EGR solenoid. Listen or feel for a clicking, indicating that the solenoid is operating.

If the solenoid does operate, you'll have to check current draw on the ground circuit. It should be less than one amp. If it is then the problem is intermittent. If it isn't then there is excessive resistance in the circuit and perform the following

1. When it's activated see if you can blow lightly through it. IF you can\'t there may be a blockage causing excessive resistance. Replace EGR solenoid as needed. If there is no blockage, disconnect the EGR solenoid and the PCM connector containing the EGR solenoid control circuit. Using a digital Volt-Ohm meter (DVOM) check resistence between the control circuit and battery ground. It should be infinite. If it isn't, then there is a short to ground on the control circuit. Repair the short to ground and retest as needed.

2. If the solenoid doesn't click as it should, disconnect the EGR solenoid connector and connect a test light between the two wires. Using the scan tool, command the EGR solenoid on. The light should light up. If it does, replace the EGR solenoid. If it does not perform the following: a. Check for 12 Volts on the ignition supply voltage to the solenoid. If it isn't present, inspect the supply circuit for an open, or a short due to chafing or breakage and re-test. b. If it still doesn't operate: then manually ground the EGR solenoid control circuit. The light should light. If it does, repair open in EGR solenoid control circuit and re-test. If it doesn't, replace EGR solenoid.

Related EGR DTC codes: P0400 - P0401 - P0402 - EGR Systems

Register

 

OBD scanner said P0430 - Catalyst System Efficiency Below Threshold (Bank 2)

I've already been through the EGR/DPFE replacement.

 

My bad I thought you said P0403. Not P0430. Here you maybe this will help.

P0430 OBD-II Trouble Code

Technical Description

Catalyst System Efficiency Below Threshold (Bank 2)

What does that mean?

Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.




Symptoms

You will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.

Causes

A code P0430 may mean that one or more of the following has happened:
•The catalytic converter is no longer functioning properly
•An oxygen sensor is not reading (functioning) properly
•There is an exhaust leak

Possible Solutions

First, inspect for exhaust leaks.

Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

 

Ya mis-read that one. Darned liz-dexia!

No, bad gas won't cause a P0420 or P0430 code.

Cat efficiency codes have no relationship (usually) to any current operating conditions as long as everything is operating normally, no vacuum leaks, misfires, etc.

New cat? Well, maybe, maybe not. Depends on the reason for the fault code and whether or not you have to undergo local emissions tests.

 

I've scheduled a diagnostic at the dealer tomorrow.

Just amazing how everything can be tip top one minute and the next, open your wallet. I guess with 200k miles I'm due. Now's the chance to replace the muffler as well and make it sound mean!

Thanks all!

 

If you can, let me know what they say. I started getting that code back in January. I erase it and it may take 3 weeks to pop back up. No drivability issues, gas mileage the same, 210,000 miles on my 02 Fx4...5.4. No exhaust leaks that I hear...if it EVER stops snowing and always causing a drippy mess to crawl underneath.....I'll take a look.

 

Code 430 is bank 2 the driver side cat monitor.
About all that needs to be done is use a Scanner to look at the live action of the rear and front Ox Sensors for switching action.
If the rear sensor tends to follow the front in switching too often the cats are at end of life for that side.
Compare to the passenger side for the same action and the difference should be seen if the passenger side is still good.
What is being looked at is the switch 'ratio' between the front and rear sensors. When it goes out of limits the code is set.
A clever way to monitor the health of the cats for Oxygen storage capacity and cleaning.
Hint. if cats are needed the dealer total cost will floor you.
Look to aftermarket from a well known company and replace the sensors as well.
With 200k on the motor the long term effects of gas additives, engine oil burning, coolant leaks etc into the exhaust chain and misfires all go toward killing the cats as well as just age, so you pretty much got you monies worth.
.
. Just to bring some info to the table on a code 403, it does not apply to these motors.
The first time it appears in Ford Docs is 2001 and applies to a Stepper motor control of EGR that is not used on these trucks unless specially equipped. Further, GM used this control system back in the 80s and 90s on some V6 motors. I've already worked on some of them in Buick and Olds V6 motors.
Good luck.

 

Is the excess switching of the rear sensor because the cat is not doing its job and it is reading gases (that should not be present) like the front sensor? Our son had a Mustang Gt once that IIRC had MIL adaptors that spoofed the computer with a reading from the rear o2 sensor.

 

Yes, that's it exactly.

Usually, a strategically placed spark plug anti-fouler or two (cough, cough) will back the downstream O2 sensor out of the exhaust stream and dampen its response enough that the codes goes away and doesn't come back.

 

LOL.....I wasn't going to bring that up...Just keep drilling and stacking till the light goes off or they drag on the ground..

 

Thanks all.

I think it's going to end up being just age. I wouldn't be surprised if its burning coolant at a slow rate, and back in January I fixed a misfire issue. I ran Autolite Copper plugs for about two months and just recently switched back to the OE platinum. Aside from a decrease in gas mileage (17 to 15), the truck seems to be running great.

If I lived anywhere else, I'd just dual it out and not worry about it. However, where I live they do emission testing for me to renew my tags. Rock Auto has the part for around $250 and we have a local shop that will do me right for install.

I'm hoping they'll find a vacuum leak, but I think it would have thrown a different code prior to the P0430. I'll try to get as much detail from the dealer as I can to report back.

My next topic may be Flowmaster vs. MagnaFlow. LOL

 

The right side is a little more expensive than the left. Let me know if you order one from Rock Auto. I have a 5% off code if you don't have one.

 

Well, the dealer did confirm that the CAT is going, if not gone. He said fuel trims look okay and the reduced mileage I was seeing was because of the cat converter going out. He also mentioned something about some PCM updates for better drive-ability, but he didn't go into detail and I didn't ask. Maybe someone here can offer more info on that...

He also told me that factory cats are around $800 each and suggested I take it down to a local muffler shop. I didn't tell him that I had already planned that.

In a nutshell, I spent $100 on piece of mind that new parts won't be damaged by a different issue and it's still gonna set me back about $400 for a CAT and a muffler installed.