Mercedes-Benz OBD2 codes

C0037 and C003A from a rear wheel speed sensor circuit

Supported by vehicle data

Owners of some Mercedes-Benz Sprinter vans report C0037 and C003A with the ABS, traction and engine lights on. In one complaint a dealer replaced a rear wheel speed sensor, and another owner mentions an earlier rear sensor recall. ABS is a safety system, so have it inspected by a qualified shop. The source is owner reports.

• C0037: Left rear wheel speed sensor circuit fault
• C003A: Right rear wheel speed sensor circuit fault

P0170 with the check engine light on

Supported by vehicle data

Mercedes-Benz bulletin 29992 lists P0170 with the check engine light on for the 1999 C230K. We only read the NHTSA summary, so it gives no cause or fix. Start with the air intake and the airflow sensor before replacing parts. We have not confirmed the bulletin is still current, so this is labelled vehicle data rather than confirmed by bulletin.

• P0170: Bank 1 fuel trim has gone out of range

P0173 fixed by replacing the air mass sensor

Supported by vehicle data

A Mercedes-Benz bulletin (070735) replaces the air mass sensor when a lit check engine light comes with P0173 on the M-Class. We only read the NHTSA summary, not the bulletin itself. We have not confirmed the bulletin is still current, so this is labelled vehicle data rather than confirmed by bulletin.

• P0173: Fuel trim at its limit on bank 2

P052E on the M274 engine, often fixed with a software update

Supported by vehicle data

A Mercedes-Benz bulletin covers the check engine light with P052E on the M274 four-cylinder engine in some Mercedes-Benz models, including the C300 and GLC300. Most cars get an engine control unit software update, while some models such as the GLC350e get a guided test and a new crankcase ventilation intake line. The bulletin says oil at the connector alone does not justify replacing the harness or engine computer. We know this bulletin only through a third-party summary, so this is labelled vehicle data rather than confirmed by bulletin.

• P052E: Crankcase ventilation (PCV) regulator valve not working as expected

P06DA from the oil pressure control solenoid on the GLC 300

Possible — needs testing

One owner of a 2020 Mercedes-Benz GLC 300 reports P06DA at 40,000 miles. The dealer named the oil pressure control solenoid in the sump and quoted engine removal on the M264 engine to replace it. No Mercedes bulletin was found, so have the wiring checked first. It needs testing to confirm the cause. The source is owner reports, a single complaint that NHTSA has not verified, so it is labelled vehicle data rather than confirmed.

• P06DA: Oil pressure control solenoid circuit open or high resistance

P0718 with limp mode in first or second gear

Possible — needs testing

A 2006 Mercedes-Benz E350 owner told NHTSA the car was stuck in first or second gear with P0718, and blamed the 722.9 transmission conductor plate. The owner says other Mercedes with the same transmission show the same codes. This is owner opinion, no cause was confirmed, and it needs testing to confirm. The source is owner reports.

• P0718: Turbine (input) shaft speed sensor signal drops in and out

P2187 reported as a lean fuel condition

Possible — needs testing

NHTSA complaints from owners of a 2016 Mercedes-Benz CLA250, a 2006 Volkswagen Passat and a 2018 Honda Accord mention P2187, read out as the system too lean at idle. The CLA250 owner reports warning lights and loss of power after fuelling, and the Accord owner says a new fuel rail was needed. Each is a single complaint, and the code needs testing to confirm the cause. The source is owner reports.

• P2187: Engine computer sees a lean mixture on bank 1 at idle: too much air for the fuel being delivered

C0037: Left rear wheel speed sensor circuit fault

Severity: Inspect soon Full C0037 guide

• Sprinter 2012–2016 · Supported by vehicle data

C003A: Right rear wheel speed sensor circuit fault

Severity: Inspect soon Full C003A guide

• Sprinter 2012–2016 · Supported by vehicle data

P0170: Bank 1 fuel trim has gone out of range

Severity: Monitor Full P0170 guide

• C-Class 1999 · Supported by vehicle data · 1 bulletin

P0173: Fuel trim at its limit on bank 2

Severity: Severity not verified Full P0173 guide

• M-Class 2001 · Supported by vehicle data · 1 bulletin

P052E: Crankcase ventilation (PCV) regulator valve not working as expected

Severity: Monitor Full P052E guide

• C-Class · Supported by vehicle data
• GLC-Class · Supported by vehicle data

P06DA: Oil pressure control solenoid circuit open or high resistance

Severity: Inspect soon Full P06DA guide

• GLC-Class 2020–2021 · Possible — needs testing

P0718: Turbine (input) shaft speed sensor signal drops in and out

Severity: Severity not verified Full P0718 guide

• E-Class 2006 · Possible — needs testing

P2187: Engine computer sees a lean mixture on bank 1 at idle: too much air for the fuel being delivered

Severity: Monitor Full P2187 guide

• CLA-Class 2016 · Possible — needs testing