Computer error code reads PO138. We have replaced the spark plugs and wires, the ignition coil, a fuel injector, the computer, the catalytic converter, and the downstream oxygen sensor. Now We are getting a PO138 error code as well as either a bank1, sensor 2 code, or a bank 2 sensor 1 code, cannot remember which one. Anyone know if I just need to replace the oxygen sensor near the manifold to fix this issue, or what. We have had nothing but issues with this van for 4 freaking years!

Dave C

• 1050 Answers
• Posted on Mar 26, 2009

SOURCE: CATALYTIC CONVERTOR - BANK 2

You have a V6 engine, bank one is the row of cylinders on the passenger (right) side, bank two is the row of cylinders on the drivers side (left). Your codes indicate an inefficiency in the cat on the left side but this could be due to a bad O2 sensor or an engine that is out of tune and overloading the cat. This car seems too new to have a bad cat. I would change the plugs and the O2 sensor after the cat before going any further. The reason I say the O2 after the cat, it's the one that is critical in sensing cat efficiency. What is the mileage?

SOURCE: MISFIRE ON CYLINDER 5.

Same problem. 94 LHS 3.5L engine. Noticeable rythmic misfire at idle. Looks like cyl 5. When I pull the injector connector off of cyl 5 the idle rythm does not change. It does if i pull the inj connector off of any other cylinder. Spark OK. Injector ok using seperate 12vdc supply (clicks). Connector to injector has pulses on it verified with a test light. Inj coil resistanceis 12 ohms, exactly what it should be.

Still need to check compression and intake manifold gasket

[email protected]

Dave C

• 1050 Answers
• Posted on May 16, 2009

SOURCE: Where is Bank 1 Sensor 1 on an 2003 Oldsmobile Sillohuette?

"Bank one" is the bank of cylinders that starts with the #1 cylinder. In this case this will be the bank of three cylinders that is closest to the firewall. Sensor #1 refers to the O2 sensor that is between the engine and the catalytic converter. So the Bank 1, sensor 1, will be the O2 sensor that is mounted in the rear exhaust manifold or tubing just before the cat.

SOURCE: two codes...need the actual physical location of oxygen sensors

pop the hood and look behind the engine in the middle....you'll see o2 sensor on the top of the exhaust pipe unplug it and remove it ............second o2 sensor is located on the same pipe under the passanger seat under the car

SOURCE: 1996 chrysler town & country electrical system problem

door ajar - probably a defective or unplugged door switch. Try pulling them, one at a time and checking the wire connections on them.