1996 Ford Explorer Trouble Codes

1996 FORD
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DETAILER1
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  • 1 POST
I just scaned my truck and it through these codes.
P0125 Insufficient coolant temperature for closed loop fuel control.
P0171 system too lean (bank1)
P0174 system too lean (bank2)
P0401 Exhaust gas recirculation flow insufficient.
If anyone could help me resolve this problem it would be greatly apreciated.I just don't want to take it to a garage and have them rip me off again and i am macanicly incline to do the job but just can't trouble shoot it. Thanks.
Feb 15, 2006 at 10:58 AM
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PEPPERMRJ
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That combination of codes is peculiar. 125 says you are not going into closed loop. Low temperature.

171 and 174 say O2s have detected a lean condition. In open loop the mixture is predetermined.

PO125
Check the connections and wires for the coolant temperature sensor. Check the operation of the sensor itself.

po171 and 174
Possible solutions include:

In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure

A code P0401 most likely means one or more of the following has happened:

The DPF (differential pressure) sensor is faulty and needs to be replaced. [b:b2e41f1fd3]Big problem for Ford.[/b:b2e41f1fd3]
There is a blockage in the EGR (most likely carbon buildup)
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum

Let us know what you find.
Feb 15, 2006 at 12:40 PM
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LOVESCARS
  • ✓Experienced Mechanic
  • 359 POSTS
try the coolant temperature sensor first
Feb 15, 2006 at 12:40 PM
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Suggested Repair

Check the coolant temperature sensor, its wiring, and connections first. Clean the MAF sensor, inspect vacuum and PCV hoses, and verify the fuel filter and fuel pressure. For the EGR code, inspect the DPFE sensor, look for carbon blockage, and check EGR valve operation and vacuum supply.

Conversation Summary

A 1996 Ford Explorer owner scanned P0125 for insufficient coolant temperature to enter closed loop, P0171 and P0174 for a lean condition on both banks, and P0401 for insufficient EGR flow. Experts said the combination was unusual because the lean readings relate to oxygen-sensor feedback normally seen in closed loop. They recommended checking the coolant temperature sensor first, then cleaning the MAF, inspecting vacuum and PCV hoses, and verifying fuel filter condition and fuel pressure. For the EGR code, they suggested checking the DPFE sensor, carbon buildup, EGR valve operation, and vacuum supply.

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