0954 P2422 Evap issue
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W204 C300 Sport
0954 P2422 Evap issue
Hey everyone, long time viewer, first time poster. Appreciate your time and suggestions on this one -- it's throwing me for a loop! Car is a 2009 C300 Sport W204 with an evap issue I can't seem to nail down. Scan tool shows 0954 / P2422 - evap charcoal canister close valve stuck shut. Looking at the monitors, car also had passed the gross evap leak, but failed the medium evap leak. Small evap leak test was not run. Only 0954/P2422 was registered, however, no codes for these leaks. Have seen several good posts here on this topic, but none seem exactly the same as my issue. Steps I have taken so far:
Charcoal canister close valve - without power, I could blow through the orig valve verifying that it is normally open. After applying +12V, the orig valve closed successfully. However, with pressure blowing against the diaphragm, as voltage is removed, the plunger did not have enough force to re-open the valve. Aha! Replaced it with a new OEM MB part and tested again outside the car. After applying +12V, the valve closes, and when voltage is removed, the plunger is strong enough to re-open even when I'm blowing into the valve. Feels like a major win, but 0954 code persists after replacement.
Charcoal canister - Disconnected evap line connection from engine bay, blew into charcoal canister and noted no blockage.
Evap lines - Disconnected evap line downstream of engine bay purge valve. Capped off same line prior to charcoal canister connection. Drew a vacuum from the engine bay back to the right wheel well and confirmed no leaks between purge valve and canister.
Gas cap - gas cap appears sealed, applied a very small amount of lubricant to rubber seal just to be safe. No issues with the gas pump clicking off during refueling.
Purge valve - Car had an evap code (unknown) a while back and this part was replaced with a URO part. As part of this recent diagnosis, I replaced it again with new OEM MB part. When using a hand vacuum pump on the intake manifold side of the purge valve, I could not establish vacuum with the brand new OEM MB part... is that normal? Seems like without voltage, the valve should be shut and a deep vacuum could be drawn against the intake manifold side. Both new and old valves acted the same, however.
Further diagnoses - Scan tool can command purge valve on and it clicks/pulses audibly with PWM signal. Scan tool can also command canister close valve to open/close. I pushed a bit of compressed air from the engine bay evap purge line downstream into the canister/fuel tank and watched pressure build on the scan tool (fuel tank pressure sensor?). This pressure immediately dissipated when commanding the canister close valve to open.
After a short drive, it's got 0954 / P2422 pending again, and I did notice at one point the OB2 I/M readiness showed a failed purge flow monitor test: $7E8 - MID $3D TID 8C. Valid range for this value is -7373 to +32767 and the car registered -11041.
A few days ago the scan tool registered -17 hPA as the pressure in the tank with the canister close valve open. Today, it registered only -3 hPa in the same condition. Converting to PSI, these are really small values and could just be temperature fluctuations? Is it possible the fuel tank pressure sensor is failing? After a lot of thinking -- is this pressure sensor the only method the PCM has to know if the canister close valve is open/shut?
Any ideas or help is greatly appreciated.
Charcoal canister close valve - without power, I could blow through the orig valve verifying that it is normally open. After applying +12V, the orig valve closed successfully. However, with pressure blowing against the diaphragm, as voltage is removed, the plunger did not have enough force to re-open the valve. Aha! Replaced it with a new OEM MB part and tested again outside the car. After applying +12V, the valve closes, and when voltage is removed, the plunger is strong enough to re-open even when I'm blowing into the valve. Feels like a major win, but 0954 code persists after replacement.
Charcoal canister - Disconnected evap line connection from engine bay, blew into charcoal canister and noted no blockage.
Evap lines - Disconnected evap line downstream of engine bay purge valve. Capped off same line prior to charcoal canister connection. Drew a vacuum from the engine bay back to the right wheel well and confirmed no leaks between purge valve and canister.
Gas cap - gas cap appears sealed, applied a very small amount of lubricant to rubber seal just to be safe. No issues with the gas pump clicking off during refueling.
Purge valve - Car had an evap code (unknown) a while back and this part was replaced with a URO part. As part of this recent diagnosis, I replaced it again with new OEM MB part. When using a hand vacuum pump on the intake manifold side of the purge valve, I could not establish vacuum with the brand new OEM MB part... is that normal? Seems like without voltage, the valve should be shut and a deep vacuum could be drawn against the intake manifold side. Both new and old valves acted the same, however.
Further diagnoses - Scan tool can command purge valve on and it clicks/pulses audibly with PWM signal. Scan tool can also command canister close valve to open/close. I pushed a bit of compressed air from the engine bay evap purge line downstream into the canister/fuel tank and watched pressure build on the scan tool (fuel tank pressure sensor?). This pressure immediately dissipated when commanding the canister close valve to open.
After a short drive, it's got 0954 / P2422 pending again, and I did notice at one point the OB2 I/M readiness showed a failed purge flow monitor test: $7E8 - MID $3D TID 8C. Valid range for this value is -7373 to +32767 and the car registered -11041.
A few days ago the scan tool registered -17 hPA as the pressure in the tank with the canister close valve open. Today, it registered only -3 hPa in the same condition. Converting to PSI, these are really small values and could just be temperature fluctuations? Is it possible the fuel tank pressure sensor is failing? After a lot of thinking -- is this pressure sensor the only method the PCM has to know if the canister close valve is open/shut?
Any ideas or help is greatly appreciated.
Last edited by adam3999; Jan 23, 2022 at 12:16 AM.
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Joined: Jun 2016
Posts: 462
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From: Panama City, FL
2020 C300, 2013 C250, 2000 Boxster S
Hey everyone, long time viewer, first time poster. Appreciate your time and suggestions on this one -- it's throwing me for a loop! Car is a 2009 C300 Sport W204 with an evap issue I can't seem to nail down. Scan tool shows 0954 / P2422 - evap charcoal canister close valve stuck shut. Looking at the monitors, car also had passed the gross evap leak, but failed the medium evap leak. Small evap leak test was not run. Only 0954/P2422 was registered, however, no codes for these leaks. Have seen several good posts here on this topic, but none seem exactly the same as my issue. Steps I have taken so far:
Charcoal canister close valve - without power, I could blow through the orig valve verifying that it is normally open. After applying +12V, the orig valve closed successfully. However, with pressure blowing against the diaphragm, as voltage is removed, the plunger did not have enough force to re-open the valve. Aha! Replaced it with a new OEM MB part and tested again outside the car. After applying +12V, the valve closes, and when voltage is removed, the plunger is strong enough to re-open even when I'm blowing into the valve. Feels like a major win, but 0954 code persists after replacement.
Charcoal canister - Disconnected evap line connection from engine bay, blew into charcoal canister and noted no blockage.
Evap lines - Disconnected evap line downstream of engine bay purge valve. Capped off same line prior to charcoal canister connection. Drew a vacuum from the engine bay back to the right wheel well and confirmed no leaks between purge valve and canister.
Gas cap - gas cap appears sealed, applied a very small amount of lubricant to rubber seal just to be safe. No issues with the gas pump clicking off during refueling.
Purge valve - Car had an evap code (unknown) a while back and this part was replaced with a URO part. As part of this recent diagnosis, I replaced it again with new OEM MB part. When using a hand vacuum pump on the intake manifold side of the purge valve, I could not establish vacuum with the brand new OEM MB part... is that normal? Seems like without voltage, the valve should be shut and a deep vacuum could be drawn against the intake manifold side. Both new and old valves acted the same, however.
Further diagnoses - Scan tool can command purge valve on and it clicks/pulses audibly with PWM signal. Scan tool can also command canister close valve to open/close. I pushed a bit of compressed air from the engine bay evap purge line downstream into the canister/fuel tank and watched pressure build on the scan tool (fuel tank pressure sensor?). This pressure immediately dissipated when commanding the canister close valve to open.
After a short drive, it's got 0954 / P2422 pending again, and I did notice at one point the OB2 I/M readiness showed a failed purge flow monitor test: $7E8 - MID $3D TID 8C. Valid range for this value is -7373 to +32767 and the car registered -11041.
A few days ago the scan tool registered -17 hPA as the pressure in the tank with the canister close valve open. Today, it registered only -3 hPa in the same condition. Converting to PSI, these are really small values and could just be temperature fluctuations? Is it possible the fuel tank pressure sensor is failing? After a lot of thinking -- is this pressure sensor the only method the PCM has to know if the canister close valve is open/shut?
Any ideas or help is greatly appreciated.
Charcoal canister close valve - without power, I could blow through the orig valve verifying that it is normally open. After applying +12V, the orig valve closed successfully. However, with pressure blowing against the diaphragm, as voltage is removed, the plunger did not have enough force to re-open the valve. Aha! Replaced it with a new OEM MB part and tested again outside the car. After applying +12V, the valve closes, and when voltage is removed, the plunger is strong enough to re-open even when I'm blowing into the valve. Feels like a major win, but 0954 code persists after replacement.
Charcoal canister - Disconnected evap line connection from engine bay, blew into charcoal canister and noted no blockage.
Evap lines - Disconnected evap line downstream of engine bay purge valve. Capped off same line prior to charcoal canister connection. Drew a vacuum from the engine bay back to the right wheel well and confirmed no leaks between purge valve and canister.
Gas cap - gas cap appears sealed, applied a very small amount of lubricant to rubber seal just to be safe. No issues with the gas pump clicking off during refueling.
Purge valve - Car had an evap code (unknown) a while back and this part was replaced with a URO part. As part of this recent diagnosis, I replaced it again with new OEM MB part. When using a hand vacuum pump on the intake manifold side of the purge valve, I could not establish vacuum with the brand new OEM MB part... is that normal? Seems like without voltage, the valve should be shut and a deep vacuum could be drawn against the intake manifold side. Both new and old valves acted the same, however.
Further diagnoses - Scan tool can command purge valve on and it clicks/pulses audibly with PWM signal. Scan tool can also command canister close valve to open/close. I pushed a bit of compressed air from the engine bay evap purge line downstream into the canister/fuel tank and watched pressure build on the scan tool (fuel tank pressure sensor?). This pressure immediately dissipated when commanding the canister close valve to open.
After a short drive, it's got 0954 / P2422 pending again, and I did notice at one point the OB2 I/M readiness showed a failed purge flow monitor test: $7E8 - MID $3D TID 8C. Valid range for this value is -7373 to +32767 and the car registered -11041.
A few days ago the scan tool registered -17 hPA as the pressure in the tank with the canister close valve open. Today, it registered only -3 hPa in the same condition. Converting to PSI, these are really small values and could just be temperature fluctuations? Is it possible the fuel tank pressure sensor is failing? After a lot of thinking -- is this pressure sensor the only method the PCM has to know if the canister close valve is open/shut?
Any ideas or help is greatly appreciated.
Last edited by alynch; Jan 23, 2022 at 03:33 PM.
