Check Engine Light and codes

1997 Ford F150, V6, 4.2L, 136K miles. Codes “P0153” and “P0401” are preventing it from passing emmissions here in Massachusetts. Anyone know which components these codes point to ??

P0153 indicates “slow response” from the O2 sensor, bank 2
P0401 indicates insufficient flow though the Exhaust Gas Recirculation valve (EGR)

Try cleaning the EGR first, and then drive it for a day or two. It is possible that both codes will disappear.

The code P0153 involves the #1 oxygen sensor on bank #2. This uaually means the cross-counts from the O2 sensor have slowed down or the sensor has become lazy. Replacing the O2 sensor will usually get rid of this code.

The code P0401 indicates insuffecient EGR gas flow. This code can be caused from a few things. A defective DPFE sensor, a defective EGR vacuum control solenoid, plugged DPFE sensor pressure ports, or a plugged exhaust gas supply tube to the EGR valve. Remove the two hoses for the DPFE sensor from the exhaust pipe and take a wire and poke it in the ports to make sure carbon isn’t restricting the ports. Remove the EGR valve and spray a brake cleaner down the supply tube to remove any carbon that might blocking the orifice in the supply tube. If none of this gets rid of the code, then the EGR vacuum control solenoid and the DPFE sensor both need to be tested to determine their proper function.


When you mention the O2 sensor on “bank #2”, do you know which O2 sensor that is ?? I just got this truck and I believe I located 2 O2 sensors ??

It will be the O2 sensor on the exhaust pipe from the left bank of cylinders before the catalytic convereter.


Is this the O2 sensor on the exhaust manifold outlet ??

The #1 oxygen sensor is the one anywhere in the exhaust from the exhaust manifold to the front of the catalytic converter. “Bank 2” is the side of the engine across from the side where the #1 spark plug is in “bank #1”.

Should be able to find this one easily now - thanks to all !