What Does P046A Mean?
The two catalyst temperature sensors on Bank 1 (sensor 1 upstream and sensor 2 downstream of the catalytic converter) are not correlating properly with each other. The ECM expects a specific temperature relationship between the inlet and outlet of the converter based on operating conditions, and the readings do not match this expected pattern. This may indicate a sensor fault or a catalytic converter efficiency issue.
Common Causes
35%
Failed upstream or downstream catalyst temperature sensor on Bank 1
25%
Wiring issue causing incorrect reading from one of the sensors
20%
Degraded catalytic converter not generating expected exothermic heat
12%
Exhaust leak between the two sensors affecting temperature readings
8%
Connector corrosion or moisture intrusion on one sensor
Diagnostic Steps
1
Compare both catalyst temperature sensor PIDs on the scan tool at operating temperature. The downstream sensor should typically read 50-100 degrees F higher than upstream during steady-state driving. If one reads significantly out of range, that sensor is suspect.
2
Allow the engine to cool completely, then check both sensor readings with key on, engine off — they should both read ambient temperature (within 10 degrees F of each other). A sensor reading significantly different is faulty.
3
Measure the resistance of each catalyst temperature sensor at the connector (disconnect them). Compare to the manufacturer's resistance-vs-temperature chart. They should be similar at the same temperature.
4
Inspect the wiring for both sensors, particularly near the exhaust where heat damage is common. Check for melted insulation, bare wires, or shorts between wires.
5
Check for exhaust leaks between the two sensor locations by visually inspecting for soot marks and listening for exhaust noise with the engine running.
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
The two catalyst temperature sensors on Bank 1 (sensor 1 upstream and sensor 2 downstream of the catalytic converter) are not correlating properly with each other. The ECM expects a specific temperature relationship between the inlet and outlet of the converter based on operating conditions, and the...
The most common cause of P046A (Catalyst Temperature Sensor 1/2 Correlation (Bank 1)) is: Failed upstream or downstream catalyst temperature sensor on Bank 1
Typical repair costs for P046A range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive short distances. If the catalytic converter is actually failing, continued driving can lead to overheating of the converter (potential fire risk in extreme cases) or further damage. If a sensor fault, there is no immediate risk. Diagnose promptly to rule out converter failure.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P046A to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Catalyst System
Difficulty
Type
Generic (SAE)
Recommended Tools
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