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2004 Chrysler Sebring 2.7L V6 OBDII Error P0137: O2 Sensor Bank 1 Sensor 2 Low Voltage - Mode $06 On-Board Monitoring Fail

Model: 2004 Sebring Fault Code: P0171 Posted: 2017-05-17 19:37

My 2004 Chrysler Sebring convertible (2.7L V6, automatic transmission, VIN R) has a persistent check engine light with fault code P0137: 'O2 Sensor Bank 1 Sensor 2 Circuit Low Voltage'. I initially replaced the upstream O2 sensor (Bank 1 Sensor 1), as it was showing 0V readings. However, after replacement, the MIL light returned and the same P0137 error persists. The OBDII report shows a failure in Mode $06 - On-Board Monitoring: Component ID $00, Test ID $72 (Manufacturer Defined), with value 0 instead of expected minimum 40. This indicates a monitoring failure for an unknown component or test. I'm unsure what this specific TID ($72) represents and whether it relates to the O2 sensor or another system. I've confirmed that Bank 1 Sensor 2 is downstream (post-catalyst), as per standard OBDII nomenclature, but I'm still unclear on how to interpret the voltage readings from both sensors. The live data shows approximately 1.27V for both Bank 1 and Bank 2 Sensor 2 — below the expected range for a healthy downstream sensor. I've replaced both upstream and downstream O2 sensors with new units, but the issue remains. I'm seeking clarification on: - What Test ID $72 specifically measures in Mode $06 - How to interpret 'Bank 1 vs Bank 2' and 'Sensor 1 vs Sensor 2' - Whether a wiring fault or ground short could be causing low voltage readings - If the failure is due to sensor malfunction, signal circuit issues, or a PCM problem Any insight into this specific OBDII monitoring failure on a 2004 Sebring would be greatly appreciated.

Related fault codes
P0171
Comments (16)
Anonymous 2017-05-18 07:36

This is a 2.7L V6 engine, not Mitsubishi — the VIN R indicates Chrysler. P0137 refers to Bank 1 Sensor 2 (downstream of catalytic converter). The failure in Mode $06 suggests an incomplete or failed on-board monitoring test for this component. Check if there's a pending code — it may be related to EVAP system testing. Live data from all O2 sensors is essential. Look at voltage readings across both banks and sensors to determine if the issue is sensor-related or wiring-based.

Anonymous 2017-05-18 08:24

Confirmed: 2004 Sebring convertible with 2.7L V6, VIN R, automatic transmission. P0137 is indeed downstream (post-cat) O2 sensor — so it's not the upstream sensor. I'll pull live data to check voltages and monitor for pending codes. If the code persists after replacing both sensors, the issue may lie elsewhere.

Anonymous 2017-05-18 08:39

Voltage readings are critical here. A low voltage reading (e.g., below 0.5V) on a downstream O2 sensor could indicate a short to ground or a failed sensor. EVAP system monitoring (TID $72) requires specific conditions — such as fuel level, engine temperature, and vehicle speed — so failure may not be directly related. For accurate diagnosis, consult your scanner's manufacturer for pending code interpretation.

Anonymous 2017-05-18 08:43

I just reviewed the OBD log again — only P0137 is pending. Let’s focus on resolving this specific code and recheck after verifying sensor voltages and live data.

Anonymous 2017-05-22 18:25

Thanks for the help. I’ve replaced both upstream and downstream O2 sensors, but the P0137 error remains. Attached is an updated OBDII log showing persistent failure in Mode $06.

Anonymous 2017-05-23 08:14

Why did you replace both sensors? First, confirm the actual voltage output from each sensor using live data. Then, try running the engine slightly richer (higher fuel trim) to see if the voltage improves — this can help determine whether it's a wiring issue or faulty sensor.

Anonymous 2017-05-23 08:46

I thought P0137 was an upstream sensor error. Clarification: Bank 1 Sensor 2 is downstream (post-cat). The OBD report shows Bank 2 Sensor 1 at 0.5V and Bank 2 Sensor 2 at 0.94V — what’s the normal voltage range for these sensors? Thanks for your help.

Anonymous 2017-05-23 10:04

Sorry, no time today — will check back later.

Anonymous 2017-05-23 13:56

Here is an updated OBDII report showing the same P0137 error and Mode $06 failure.

Anonymous 2017-05-24 08:11

Confusion about engine type — check the 8th character of VIN: R or T? Options: • 2.7L V6 VIN R Automatic • 2.7L V6 VIN R Standard • 2.7L V6 VIN R U/K • 2.7L V6 VIN T Automatic • 2.7L V6 VIN T Standard • 2.7L V6 VIN T U/K

Anonymous 2017-05-24 08:30

It's a VIN R with automatic transmission — 2004 Chrysler Sebring Convertible, 2.7L V6.

Anonymous 2017-05-24 11:50

A dedicated OBDII scanner is required to read live sensor voltages. For P0137 (O2 Sensor Bank 1 Sensor 2 Circuit Low), the code triggers when the PCM detects voltage below 2.402V for at least 9 seconds during engine operation. Possible causes: • Shorted O2 signal or return circuit to ground • Faulty O2 sensor • Wiring issues (especially in high-temperature areas) • PCM failure

Anonymous 2017-05-30 16:38

Thanks so much for the detailed explanation. I’ve replaced both upstream and downstream O2 sensors. In Mode $06, Component ID $00 fails with value 0 instead of minimum 40 — what does this TID ($72) represent? Any idea what component it's monitoring?

Anonymous 2017-05-31 15:36

Hello. CID (Component ID) and TID (Test ID): The failure occurs at TID $72 with CID $00, showing value 0 vs expected minimum of 40. Previously, when CID was $7F, the test passed (65535, N/A). This inconsistency suggests a parameter mismatch — possibly due to sensor signal or calibration issues. The OBD data shows both Bank 1 and Bank 2 Sensor 2 at ~1.27V, which is low for a downstream sensor. Why does it fail only on Bank 2? This is confusing.

Anonymous 2017-05-31 20:46

Thanks, Atip. I notice the same pattern — sometimes it passes, sometimes fails. I don’t know what TID $72 measures. Can you clarify: Is Bank 1 upstream and Bank 2 downstream? And what is the difference between Sensor 1 and Sensor 2 in this system? Does each bank have only one O2 sensor?

Anonymous 2017-06-01 14:32

See this helpful guide for OBDII component identification: https://www.densoproducts.com/learning- ... tion-guide