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A catalytic converter code or a rotten egg smell does not automatically mean you need a new converter. Route 66 Auto Repair in Upland tests the converter, the oxygen sensors around it and the engine conditions that feed it, so you only replace what has actually failed. The diagnostic fee is stated at the counter before testing, and it applies to approved related repair.
What are the signs of a converter problem?
- A check engine light with a catalyst efficiency code, often P0420 or P0430
- A rotten egg or sulfur smell after hard driving
- A rattle from the converter shell when you tap it or start the car
- Weak power on the climb up the 210 toward the Cajon Pass
- Heat you can feel through the floor above the converter
What can make a good converter look bad?
The engine computer judges the converter by comparing the oxygen sensor ahead of it with the one behind it. A healthy converter smooths out the rear signal. If the rear sensor is slow or its wiring is damaged, the comparison goes wrong and a good converter gets blamed. An exhaust leak between the two sensors can do the same thing. That is why a sensor check, and sometimes oxygen sensor replacement, comes before a converter quote.
Real failures have causes too. A misfire dumps raw fuel into the converter, where it burns and can melt the core. Oil burning and coolant leaks coat the core and choke it. If one of those is present, we find it first, often through check engine light diagnostics. A bottle of additive cannot repair a melted or broken core.
Our converter testing process
Step 1: Scan and review data
We read codes and freeze-frame data, then watch both oxygen sensors while the engine runs.
Step 2: Check for leaks and misfires
We look for exhaust leaks near the sensors and for misfire history that could harm the converter.
Step 3: Inspect the shell and shields
On the lift we tap the converter for loose core pieces and check its heat shields and connections.
Step 4: Report the cause
You get a written estimate that separates the converter itself from any upstream repair it needs.
What's included in converter service
Included on the work order
- 01Code and freeze-frame review
- 02Upstream and downstream oxygen sensor data check
- 03Leak check near both sensors
- 04Misfire history review
- 05Converter shell and heat shield inspection
- 06Written findings with the root cause named
How urgent is a converter concern?
Need now: call
- A flashing check engine light
- A glowing or very hot converter, or a burning smell
- Sudden loss of power on a grade
Need later: book
- A steady efficiency code with no drivability change
- A light shell rattle from a loose heat shield
How pricing and timing work
Testing is billed as diagnosis, with the fee stated before we start. After that, the price depends on what we find: a sensor, a leak, an engine fix or the converter. Most testing fits in one visit when the board allows. AAA members get 10% off parts and labor, up to $75. If replacement is needed, see catalytic converter replacement.
Frequently asked questions
Does a catalyst efficiency code mean my converter is dead?
Not always. A slow rear oxygen sensor, a leak between the sensors or a misfire can trigger the same code. We check those before recommending a converter, so you do not buy one you did not need.
What causes a rotten egg smell from my car?
Sulfur in fuel passing through a converter that is working too hard, often because the engine is running rich. A fuel mixture problem is the usual root cause, and fixing it often ends the smell.
Can I keep driving with a converter code?
If the light is steady and the car drives normally, usually for a short while. If the light flashes, or you lose power or smell burning, stop driving and call (909) 608-7699. We accept tow-ins.