Service bulletin SB20-H-001

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

NHTSA's summary

VEHICLES PRODUCED PRIOR TO JANUARY 2, 2019 SOME CUSTOMERS MAY COMPLAIN ABOUT AN ILLUMINATED CHECK ENGINE LIGHT SETTING SHORTLY AFTER STARTING THE ENGINE. IF THE REASON FOR THE CHECK ENGINE LIGHT ILLUMINATING IS DTC P0027, THE MOST LIKELY CAUSE IS LOW BRAKE AIR PRESSURE. DTC P0027 MAY SET WHEN THE BREAK AIR PRESSURE IS VERY LOW OR AT 0 PSI AT THE TIME THE VEHICLE IS STARTED. THE BREAK AIR PRESSURE CAN BE DEPLETED (RESULTING IN LOW OR 0 PSI) AFTER THE AIR SYSTEM HAS BEEN SERVICED OR THE VEHICLE HAS BEEN STORED FOR A LONG PERIOD OF TIME. IF DTC P0027 CONTINUES TO SET EVEN THOUGH THER ARE NO AIR SYSTEM LEAKS THAT MAY BE QUICKLY DEPLETING THE AIR SUPPLY OR CAUSING DELAYS IN THE BUILDUP OF AIR PRESSURE AND THE EXHAUST BRAKE IS FUNCTIONING PROPERLY, FOLLOW THE SERVICE PROCEDURE IN THIS BULLETIN TO REROUTE AIR DRYER LINES FOR IMPROVED AIR SUPPORT TO THE EXHAUST BRAKE.

The document

• NHTSA's copy of the document (PDF)
• If that address does not open, try this one

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Brakes

Trouble codes named

P0027

Listing a model year does not mean every vehicle of it is concerned: the document says which.

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