Just experienced the following warnings which have cleared:
- ESC Not Available,
- Reduced Braking Performance,
- Uphill/Downhill Assist Not Available,
- TSA Not Available
All of the above point to one shared system: the ABS/ESC sensor network, especially the wheel speed sensors and steering angle alignment.
The diagnosis of the problem is gleaned from sources on the internet. I will report further upon examination.
What the warnings actually mean
All five systems rely on accurate wheel‑speed data, steering angle data, and stable voltage. If any of these inputs go bad, the Grenadier disables all dependent systems at once. That’s why you get a “Christmas tree” of warnings.
Most common root causes (with evidence)
1) Wheel speed sensor fault or damage
Owners report:
- Damaged rear wheel sensor causing the exact same warnings, fixed by replacing the sensor.
- Stones bending the tone ring teeth or mud blocking the sensor.
- Mud/dirt on the ABS rings causing intermittent faults until cleaned.
Why it triggers everything:
If one wheel’s speed reading drops out, the ESC module shuts down ESC, TSA, hill assist, downhill assist, and brake assist.
2) Incorrect steering wheel angle / poor wheel alignment
This is surprisingly common on new Grenadiers.
- A misaligned steering wheel or incorrect factory geometry caused the same warnings; a four‑wheel alignment fixed them completely.
- Another owner had faults disappear after a proper alignment by a specialist, not the dealer.
Why it matters:
If the steering angle sensor disagrees with wheel‑speed data, the ESC system thinks the vehicle is sliding.
3) Low or unstable battery voltage.
Multiple owners report the warnings appearing when the battery isn’t fully charged.
- If the battery isn’t “perfectly charged,” these warnings can appear.
- Turning the key too quickly (not letting systems wake up) can also trigger them.
Why it matters:
The ESC/ABS module is voltage‑sensitive; low voltage causes cascading system shutdowns.
Less common but documented causes
- Wiring harness issue behind the steering wheel — there is an active campaign for this.
- Debris on ABS rings — fixed by cleaning with detergent and water.
- Stone damage to tone ring — confirmed by owners.
What to check first (in order)
- Rear wheel speed sensors
- Look for mud, stones, bent tone ring teeth, or damaged wiring.
- Wheel alignment & steering angle calibration
- A proper 4‑wheel alignment (not just front tracking) has fixed this for several owners.
- Battery health
- Check voltage and charge state.
- Start the vehicle by pausing briefly at ignition stage 2 before cranking.
- ABS ring cleanliness
- Clean the rings with mild detergent and water (no pressure washer).
- Dealer check for steering‑column wiring campaign
- Some vehicles need a harness fix.
Most likely cause for your symptoms
Based on the pattern and frequency of identical reports, the rear wheel speed sensor or wheel alignment/steering angle are the top two candidates.
If your warnings appear every drive, not intermittently, that strongly points to:
- A damaged or disconnected wheel speed sensor, or
- A badly out‑of‑spec steering angle reading
