Service engine soon light on after car wash

Tiny
DCKELLEY
  • MEMBER
  • 1998 BUICK PARK AVENUE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
I took my car to the car wash yesterday and after the wash I had a service engine soon light on.
took the car to a parts store and the codes they got were o2 sensor delay and catalytic converter below threshold or something like that. Help.
Thursday, March 28th, 2019 AT 1:57 PM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

What are the exact code numbers so I can help you?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Roy
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Thursday, March 28th, 2019 AT 3:17 PM
Tiny
ASEMASTER6371
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There was no text in the response.

Roy
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Thursday, March 28th, 2019 AT 5:42 PM
Tiny
DCKELLEY
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  • 125 POSTS
P0133 and p0420. I had them reset today and they haven't returned. I'm hoping something just got wet during the car
wash.
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Thursday, March 28th, 2019 AT 5:43 PM
Tiny
DCKELLEY
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  • 125 POSTS
Information above.
By the way ignore the ralph malph member as it's me. Any idea how to delete a profile? I accidentally sighed up twice. Jeez only I could do that.
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Thursday, March 28th, 2019 AT 6:18 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, the 133 is a slow response to the O2 sensor.

I attached a description of the code below.

The 420 is a cat code. You need a cat converter. The precious metals inside the converter are worn out and the cat needs to be replaced.

Clearing the codes does nothing. They will return when they fail the internal testing from the PCM three times in a row.

Roy

CIRCUIT DESCRIPTION

The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitoring period the PCM counts the number of times that the a rich to lean and lean to rich response is indicated and adds the amount of time it took to complete all transitions. With this information, an average time for each transition can be determined. If the average response time is too slow, a DTC P0133 will be set. A lean to rich transition is indicated when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean transition is indicated when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is likely to be malfunctioning and should be replaced.

CONDITIONS FOR RUNNING THE DTC

No Throttle Position (TP) sensor, EVAP system, misfire, Intake Air Temperature (IAT) sensor, Manifold Absolute Pressure (MAP) sensor, fuel trim, fuel injector circuit, EGR Pintle Position, Engine Coolant Temperature (ECT) sensor, HO2S heater circuit sensor 1, Crankshaft Position (CKP), or Mass Air Flow (MAF) sensor DTC(s) present

Engine has been running in Closed Loop fuel control for at least 60 seconds.

Engine speed is between 1000 RPM and 3000 RPM.

Engine Coolant Temperature greater than 50°C (122°F).

Mass Air Flow between 10 g/s and 30 g/s.

CONDITIONS FOR SETTING THE DTC

VIN K - HO2S 1 lean to rich average transition response time during the sample period was longer than 140 milliseconds or rich to lean average transition response time during the sample period was longer than 107 milliseconds.

VIN 1 - HO2S 1 lean to rich average transition response time during the sample period was longer than 130 milliseconds or rich to lean average transition response time during the sample period was longer than 110 milliseconds.

ACTION TAKEN WHEN THE DTC SETS

The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.

The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.

DIAGNOSTIC AIDS

Check for the following conditions:

Poor Connections at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the HO2S 1 display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the malfunction. If DTC P0133 cannot be duplicated, Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table:

2. Verifies that the malfunction is currently present.

3. HO2S transition time, ratio, and switching DTCs set for multiple sensors indicate probable contamination. Before replacing the sensors, isolate and correct the source of the contamination to avoid damaging the replacement sensors.
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Thursday, March 28th, 2019 AT 7:14 PM
Tiny
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After 20 or 30 restarts and a couple hundred miles the light never did come back on.
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Wednesday, April 3rd, 2019 AT 9:55 PM
Tiny
ASEMASTER6371
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It will. It has to fail its own internal tests three times in a row before the light will come on.

It is not a matter of if. It is a matter of when the light will return.

Roy
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Thursday, April 4th, 2019 AT 4:25 AM

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