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Title: P1556 vs P1557 (pos/neg deviation) codes Post by: nyet on October 01, 2013, 11:11:59 AM http://wiki.ross-tech.com/wiki/index.php/17964/P1556/005462
17964/P1556 - Charge Pressure Control: Negative Deviation Possible Symptoms Reduced power output Limp mode Possible Causes Boost Pressure too Low [I believe this is wrong!] Hoses/Pipes incorrect connected, disconnected or leaking Charger Pressure Control defective VNT (variable nozzle turbo): nozzles stuck Solenoid Valve for Boost Pressure Control (N75) defective Possible Solutions Check Hoses/Pipes to/between Components Check Solenoid Valve for Boost Pressure Control (N75) Check / Clean / Replace Charge Pressure Control Check / Clean mechanism for variable nozzles http://wiki.ross-tech.com/wiki/index.php/17965/P1557/005463 17965/P1557/005463 - Charge Pressure Control: Positive Deviation Possible Symptoms Reduced power output Limp mode Possible Causes Boost Pressure too High [I believe this is wrong!] Hoses/Pipes incorrect connected, disconnected, blocked or leaking Charger Pressure Control defective VNT (variable nozzle turbo): nozzles stuck Solenoid Valve for Boost Pressure Control (N75) defective Possible Solutions Check Hoses/Pipes to/between Components Check Solenoid Valve for Boost Pressure Control (N75) Check / Clean / Replace Charge Pressure Control Check / Clean mechanism for variable nozzles ... so why is it that when i was getting underboost, i was throwing a pos deviation code? http://nefariousmotorsports.com/forum/index.php/topic,871.0title,.html I always thought pos deviation is lde>>0, neg deviation is lde<<0, where lde is (setpoint - process), NOT (process - setpoint). Does ross-tech have it backwards? Title: Re: P1556 vs P1557 (pos/neg deviation) codes Post by: nyet on January 05, 2015, 12:18:07 PM http://wiki.ross-tech.com/wiki/index.php/17963/P1555/005461
17963/P1555 - Boost Pressure Control: Upper Limit Exceeded Possible Symptoms Reduced power output Limp mode Possible Causes Boost Pressure too High Hoses/Pipes incorrect connected, disconnected, blocked or leaking Charger Pressure Control defective VNT (variable nozzle turbo): nozzles stuck Solenoid Valve for Boost Pressure Control (N75) defective Possible Solutions Check Hoses/Pipes to/between Components Check Solenoid Valve for Boost Pressure Control (N75) Check / Clean / Replace Charge Pressure Control Check / Clean mechanism for variable nozzles Title: Re: P1556 vs P1557 (pos/neg deviation) codes Post by: nyet on January 05, 2015, 12:26:09 PM Conclusion:
CLALDO (0x10710 index 0x63) can generate P1555 (0x12FDC) CLALDRA (0x10713 index 0x66) can generate P1556 and P1557 (0x12FF4) Note that 12FF4 contains 1557 1556 1556 1556 Which means the first entry is positive deviation (P1557), and the rest of the entries are negative deviation (P1556) I do not know how minError/maxError in correlate with the various DTC slots yet. As far as I can tell: lde too positive (underboost: lde>EDLDRP) leads to LDRA MinError, which generates P1557, positive deviation lde too negative (overboost) should generate P1556, negative deviation However, according to the FR, only MinError can be set in dldr-ldra, so I'm not sure how P1556 is set, or even how entries other than the first in the manufacturer DTC can be generated. |