2004 Mazda 3 - P2188, P2178, P0126 - O2 sensor faulty?

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January-20th-2012 | 02:47 PM

ryanmetcalf

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Joined: Jan 2012

Posts: 5

From: Kansas

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2004 Mazda 3 - P2188, P2178, P0126 - O2 sensor faulty?

I drive a 2004 Mazda 3 Hatchback (2.3L) w/approx 126k miles, bought it used 9-10 months ago, and to my knowledge it's all stock under the hood.

Almost daily, I'm tripping 2 of 3 codes, I log it, clear it, and it arrives the next day (or sooner)

It's always this fault as current:
P2188: System Too Rich at Idle bank1

Coupled with either of these two as "pending": (only gotten P2178 once or twice, P0126 is much more common)
P2178: System Too Rich Off Idle bank1
P0126: Insufficient Coolant Temperature for Stable Operation

Here's what diagnostic data I've collected thus far
Diagnostic Scan Tool: PLX Kiwi Bluetooth http://www.plxkiwi.com/kiwibluetooth/
Application: Torque (on Android)

Code:

Fault log report generated by Torque for Android
=================================================

Vehicle VIN: JM1XXXXXXXXXX6525
Vehicle Manufacturer: Mazda
Vehicle Calibration ID: L3S3EG050L3VS020

Current Fault Log - 3-19-12
------------------
P2188: System Too Rich at Idle bank1

Pending Fault Log
------------------
P2178: System Too Rich Off Idle bank1
P2188: System Too Rich at Idle bank1

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
U0184: null

End of report.

Code:

Fault log report generated by Torque for Android
=================================================

Vehicle VIN: JM1XXXXXXXXXX6525
Vehicle Manufacturer: Mazda
Vehicle Calibration ID: L3S3EG050L3VS020

Current Fault Log
------------------
P2188: System Too Rich at Idle bank1

Pending Fault Log
------------------
P0126: Insufficient Coolant Temperature for Stable Operation
P2188: System Too Rich at Idle bank1

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
U0184: null

End of report.

and also used Torque to log the output of both of my 02 sensors (not sure of exact logging frequency) whilst driving with cruise set (they couldn't both be logged at same time, so I logged each whilst on flat terrain going same speed).

Then had done some reading about O2 sensors at http://www.aa1car.com/library/o2sensor.htm
I thought about going back and doing a retest using idle or stationary parameters

Anyone have any suggestions as what I need to test, investigate, replace?

January-20th-2012 | 02:54 PM

ryanmetcalf

Thread Starter

Registered User

Joined: Jan 2012

Posts: 5

From: Kansas

Could this
https://www.mazda3club.com/mazda-service-info-111/mazda3-code-p2188-2178-a-41787/
Be what's triggering the too rich mixture errors?

I'm still not sure what gets the coolant temp error (almost always is tripped or pending when the p2188 trips)

January-23rd-2012 | 03:45 PM

ryanmetcalf

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Registered User

Joined: Jan 2012

Posts: 5

From: Kansas

Quote:

Originally Posted by ryanmetcalf

Could this
https://www.mazda3club.com/showthread.php?t=41787
Be what's triggering the too rich mixture errors?

I'm still not sure what gets the coolant temp error (almost always is tripped or pending when the p2188 trips)

Did some air flow sensor testing (taking MAF sensor readings at various RPM), and I'm still not sure I want to tackle that wire replacement in the above linked bulletin, did anyone do it? Have photos?

MAF readings

at 800rpm (approx lukewarm idle in Neutral)