98 Toyota Tacoma
mingo
01-03-2008, 10:03 PM
Check Engine Light On Code P0420 Catalyst System Efficienty Below Threshold (bank 1 )
What Does This Mean... Help Me Fix It.
Thanks
What Does This Mean... Help Me Fix It.
Thanks
Brian R.
01-03-2008, 11:20 PM
Your HO2 sensor after the catalytic converter is not responding normally.
1. Check for leaks in the exhaust system between the engine and the cat converter (loose connection, rusted area, or burned out seal)
2. HO2 or A/F ratio sensor before cat converter is bad (remove connector and measure resistance between terminals +B and HT - should be 0.8-1.4 ohms cold).
3. HO2 sensor after cat converter is bad (measure resistance as above - should be 11-16 ohms cold).
4. Cat converter is bad.
If you need to replace a sensor, bring your VIN to a Toyota dealer and get the correct part number for your engine. There is only one that works correctly, but at least two available. You don't have to buy the part from Toyota, but you have to have the correct part number.
1. Check for leaks in the exhaust system between the engine and the cat converter (loose connection, rusted area, or burned out seal)
2. HO2 or A/F ratio sensor before cat converter is bad (remove connector and measure resistance between terminals +B and HT - should be 0.8-1.4 ohms cold).
3. HO2 sensor after cat converter is bad (measure resistance as above - should be 11-16 ohms cold).
4. Cat converter is bad.
If you need to replace a sensor, bring your VIN to a Toyota dealer and get the correct part number for your engine. There is only one that works correctly, but at least two available. You don't have to buy the part from Toyota, but you have to have the correct part number.
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