# Check Engine Light and codes **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [November 19, 2009, 3:11pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712 "2009-11-19T15:11:47Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ebko87](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@ebko87](https://community.cartalk.com/u/ebko87)\ **Post date:** [November 19, 2009, 3:11pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/1 "2009-11-19T15:11:47Z")
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 ?? ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [November 19, 2009, 3:28pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/2 "2009-11-19T15:28:35Z")
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. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 19, 2009, 4:56pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/3 "2009-11-19T16:56:09Z")
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. Tester ---
**Author:** ![ebko87](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@ebko87](https://community.cartalk.com/u/ebko87)\ **Post date:** [November 19, 2009, 5:20pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/4 "2009-11-19T17:20:40Z")
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 ?? ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 19, 2009, 5:41pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/5 "2009-11-19T17:41:06Z")
It will be the O2 sensor on the exhaust pipe from the left bank of cylinders before the catalytic convereter. Tester ---
**Author:** ![ebko87](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@ebko87](https://community.cartalk.com/u/ebko87)\ **Post date:** [November 19, 2009, 10:40pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/6 "2009-11-19T22:40:18Z")
Is this the O2 sensor on the exhaust manifold outlet ?? ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [November 20, 2009, 4:10am UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/7 "2009-11-20T04:10:23Z")
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”. ---
**Author:** ![ebko87](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@ebko87](https://community.cartalk.com/u/ebko87)\ **Post date:** [November 20, 2009, 12:49pm UTC](https://community.cartalk.com/t/check-engine-light-and-codes/39712/8 "2009-11-20T12:49:30Z")
Should be able to find this one easily now - thanks to all !