But to clear codes, you need a scan tool. Codes will stay in memory 50 ignition cycles. On these systems, flash codes repeat three times. On a typical General Motors application with a Bosch 2U ABS system (1990-94 fullsize rear-wheel drive passenger car), for example, codes can be accessed manually by grounding terminal 'H' on the ALDL connector, then counting flashes of the ABS lamp. On ABS systems that provide manual flash codes (such as Bosch 2E, 2S, 2U and 3, Kelsey-Hayes RWAL and 4WAL, and ITT Teves Mark 2), you do not need a scan tool but using one reduces the chance of misreading a code. If the light is on, you have to perform pinpoint circuit tests to isolate the fault. On early Bosch 2 ABS import systems, there are no codes. Pulling trouble codes from an ABS system may be easy or difficult depending on the application. Either way, you will have to pull the code to figure out what is wrong. If you are not dealing with a real problem the ABS system has self-diagnosed, you may have a 'false' code that was set by some combination of circumstances.

Reading Antilock Brake Codes by Larry Carley copyright 2019 Īn ABS warning lamp that is on usually means trouble. Auto Repair Library, Auto Parts, Accessories, Tools, Manuals & Books, Car BLOG, Links, Index

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