What Does P046B Mean?
The two catalyst temperature sensors on Bank 2 (sensor 1 upstream and sensor 2 downstream of the catalytic converter) are not correlating properly. The ECM detects a discrepancy between the expected temperature relationship at the converter inlet and outlet on Bank 2. This mirrors P046A but for the opposite bank on V-type or horizontally-opposed engines.
Common Causes
35%
Failed upstream or downstream catalyst temperature sensor on Bank 2
25%
Wiring damage or degradation in Bank 2 sensor circuits
20%
Bank 2 catalytic converter degradation affecting temperature differential
12%
Exhaust leak on Bank 2 between the sensor locations
8%
Connector corrosion or moisture intrusion on one Bank 2 sensor
Diagnostic Steps
1
Compare both Bank 2 catalyst temperature sensor PIDs at operating temperature. The downstream sensor should read 50-100 degrees F higher than upstream during steady-state cruising. Compare this differential to the Bank 1 sensors to see if one bank is abnormal.
2
With the engine cold, verify both Bank 2 sensors read near ambient temperature (within 10 degrees F of each other and of the Bank 1 sensors). A discrepancy at cold startup isolates a faulty sensor.
3
Disconnect each Bank 2 catalyst temperature sensor and measure resistance. Compare to manufacturer specs and to the corresponding Bank 1 sensor readings — they should be similar at equivalent temperatures.
4
Inspect Bank 2 sensor wiring for heat damage, especially where the harness routes near exhaust manifolds, turbochargers, or catalytic converters. Look for melted loom, bare wires, or changed wire color from heat exposure.
5
Check for exhaust leaks on Bank 2 between the upstream and downstream sensor locations. Use a smoke machine or listen carefully with the engine running.
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
The two catalyst temperature sensors on Bank 2 (sensor 1 upstream and sensor 2 downstream of the catalytic converter) are not correlating properly. The ECM detects a discrepancy between the expected temperature relationship at the converter inlet and outlet on Bank 2. This mirrors P046A but for the ...
The most common cause of P046B (Catalyst Temperature Sensor 1/2 Correlation (Bank 2)) is: Failed upstream or downstream catalyst temperature sensor on Bank 2
Typical repair costs for P046B 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 for short distances. A failing catalytic converter can overheat in extreme cases. If only a sensor fault, there is no immediate safety concern. Have it diagnosed soon to differentiate between a sensor and converter issue.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P046B to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Catalyst System
Difficulty
Type
Generic (SAE)
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