Brake system, power, front disc, rear drum, cast iron, antilock, front and rear wheel

Years 1996, 1998–05 Models 6 Factory citations 18

Also described as Anti-lock power brakes, front disc and rear drumBrake system, power front disc, rear drum, cast iron, antilock front and rear wheelBrake system, front disc, rear drum, antilock

Also documented for Chevrolet GMC Oldsmobile Pontiac Saturn

Documented applications

Century — A-body (1982–1996)

1996 Confirmed

Standard

Century — W-body (1997–2005)

1998–2003 Factory-verified

GM factory document — 1998 buick century rpo code list, p.1.
GM factory document — 1999 buick century rpo code list, p.1.
GM factory document — 2000 buick century rpo code list, p.1.
GM factory document — 2001 buick century rpo code list, p.1.
GM factory document — 2002 buick century rpo code list, p.1.
GM factory document — 2003 buick century rpo code list, p.1.

LeSabre — H-body (1992–1999)

1998–1999 Factory-verified

GM factory document — 1998 buick lesabre rpo code list, p.1.
GM factory document — 1999 buick lesabre rpo code list, p.1.

Regal — W-body (1997–2004)

1998–2003 Factory-verified

GM factory document — 1998 buick regal rpo code list, p.1.
GM factory document — 1999 buick regal rpo code list, p.1.
GM factory document — 2000 buick regal rpo code list, p.1.
GM factory document — 2001 buick regal rpo code list, p.1.
GM factory document — 2002 buick regal rpo code list, p.1.
GM factory document — 2003 buick regal rpo code list, p.1.

Rendezvous — U-body / GMT257 (2002–2007)

2002–2005 Factory-verified

The 2002 list omits "cast iron".

GM factory document — 2002 buick rendezvous awd rpo code list, p.1.
GM factory document — 2003 buick rendezvous awd rpo code list, p.1.
GM factory document — 2005 buick rendezvous awd rpo code list, p.1.

Skylark — N-body (1992–1998)

1998 Factory-verified

other lists word JM4 as a power brake system with cast iron rotors and four-wheel antilock; this list's wording is the short form.

GM factory document — 1998 buick skylark rpo code list, p.1.

This page aggregates every documented appearance of JM4 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.