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The heater circuit code 41 is almost always caused by a failed O2 sensor. The newer 4 wire sensors have an internal heater element that enables them to reach operating temperature faster than the older 1 or 2 wire sensors without the heater that rely on exhaust gas to heat them. It's actually a pretty common problem and a new primary O2 sensor, the one closest to the engine, should fix it. Knock sensor code 23 means you need to replace the knock sensor. Code 78 is the automatic transmission control unit (TCU). You can usually find a good replacement at a salvage yard for about $50-75. You say you replaced the TCU, so the code may just need to be reset or may vanish once you replace the O2 sensor and the knock sensor.

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Yes, I replaced the TCU when the car started acting up not shifting into 1st gear and cyceling between 1st and 2nd at aquward times and normally when it rains and at 45mph! I thought the new TCU would fix the problem but it appears to have only shifted it or it has new problems, if thats possible.

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