W140 S320 - ABC (Active Body Control) error code C1525 - is it the height sensor or the ride strut

Started by Hugo_Darlinghurst, 12-05-2023 02:48 PM. 9 replies. 1,847 views.

12-05-2023 02:48 PM

Hugo_Darlinghurst Senior Member

★ Gold

Join Date: Feb 2010
Location: Darlinghurst NSW
Posts: 524
Club: Mercedes Classic Drivers Australia (MCDA) - chapter committee
Car: 1968 W108 280SE 5.0 Coupe

small drama.

A diagnostic question. Friend's 1996 S320 (W140 short wheelbase, ABC equipped). Error code C1525 in the ABC module - "Front right height sensor signal implausible".

Diagnostic options:

Height sensor itself has failed

Sensor wiring or connector compromised

Ride strut compromised - sensor reads correctly but the strut is not responding, producing the implausible signal

The car rides level statically. Dynamically it pitches slightly under hard braking which is not normal for an ABC-equipped W140. Suggests the front-right strut is partially compromised.

Anyone diagnosed and isolated C1525 specifically?

12-05-2023 04:18 PM

Vasilios_Billy

Lifetime Benzer

Join Date: Mar 2008
Location: Campbelltown NSW
Posts: 1,782
Club: M.A.L.A.K.A.S.
Car: 2020 AMG GT C

Hugo.. C1525 on W140 ABC is front-right height sensor not agreeing with the other three sensors. fault can still be sensor, wiring or strut.

With dynamic pitch under braking I lean strut. static height holds because pump has pressure. under load the strut cant respond, sensor reports chassis position not matching command, module logs C1525.

Need XENTRY / HHT data-log road test, not just OBD scan. trace will show if sensor values make mechanical sense.

Pressure test confirms. good strut about 120 bar at rest and responds within 100ms. bad one is slow or low pressure.

Front-right ABC strut in 2018: $4,800 OE, about $2,800 reman tested. labour about 3 hours.

15-05-2023 11:18 AM

Hugo_Darlinghurst Senior Member

★ Gold

Join Date: Feb 2010
Location: Darlinghurst NSW
Posts: 524
Club: Mercedes Classic Drivers Australia (MCDA) - chapter committee
Car: 1968 W108 280SE 5.0 Coupe

Vasilios - I have arranged the road-test diagnostic at Mercedes-Benz Specialist Werkstatt Rosebery this Friday.. will report back with the data-log findings..

22-05-2023 09:48 AM

Hugo_Darlinghurst Senior Member

★ Gold

Join Date: Feb 2010
Location: Darlinghurst NSW
Posts: 524
Club: Mercedes Classic Drivers Australia (MCDA) - chapter committee
Car: 1968 W108 280SE 5.0 Coupe

fyi data-log road test found front right strut cooked. 78 bar at rest vs 120 bar spec. reman strut in, $2,800, code cleared, pitch under braking gone. Vasilios as ever..

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