Codes PO404, 405, PO457, 456. replaced gas cap with mopar cap. Light didn't go off right away, but when i filled up, it went off, but came back on at about 100 miles. How serious are these issues, and am...
It's not an immediate danger, but certainly needs attention for improved efficiency, driveability, and best gas mileage. And to protect expensive parts, like the catalytic converter, for one.
You have two issues with those codes. P0404 and 05 refer to the EGR operation. Exhaust Gas Recirculation is an emissions system, it helps regulate combustion temperatures inside the cylinders. P0405 is EGR, sensor A circuit low. That fault probably also set the P0404 as it says circuit range or performance of EGR is at fault. This is the more serious issue. When you can, it needs some tests of the EGR operation, finding the problem in the circuit of that sensor, or whatever it is. The egr valve may not be opening enough, or it may be a wiring problem, should be easy to check and test.
The other codes are the ones that drive people crazy, and sometimes technicians, too. P0456 is Evaporative Emission Control System, Leak Monitor small leak detected. I didn't see 0457 in a generic listing of codes, it may be more specific to Chrysler, but I'm sure it is related to 0456, it's in the EVAP system at any rate. Good that you already tried a new gas cap, that often sets the codes. A small leak somewhere between the charcoal canister and the gas tank's vent line where the gas fumes travel through, and the piping of the canister to the engine and the purge valve, all that has to be checked for a small leak. Shops use a trick: a smoke test where they blow fog or smoke into the system and then start looking for leaks. This issue doesn't affect drivability at all. Don't let it drive you crazy !
Oct 03, 2013 |
1999 Lincoln Navigator