The P1707 error code on a Maruti Suzuki WagonR (Automatic Transmission / AMT or AGS model) generally refers to a “Torque Reduction Signal Circuit Malfunction” between the ECM (Engine Control Module) and the TCM (Transmission Control Module).

Let’s break this down for you 👇

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⚙️ Meaning of Code P1707 (WagonR AT / AMT)

Code: P1707
Description: Torque Reduction Signal Circuit Malfunction
System: Transmission / Engine Control Communication

The ECM and TCM communicate to coordinate torque reduction during gear shifts. When the TCM requests torque reduction (to make gear shifting smoother), the ECM briefly reduces engine torque.
If this signal is missing, delayed, or out of range, the TCM sets P1707.

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🚨 Possible Causes

1. Wiring or Connector Issues

Loose, corroded, or damaged connectors between ECM and TCM.

Damaged wiring harness (common near transmission or battery area).

2. Faulty ECM or TCM

Internal fault in either module (rare, but possible).

3. Grounding or Power Supply Issues

Poor battery ground or low system voltage.

Bad engine/transmission ground strap.

4. Software / Calibration Error

Sometimes caused by outdated ECM/TCM firmware — may require a reflash at a Suzuki service center.

5. Sensor Issue

Throttle position sensor, crankshaft sensor, or other input sensor giving erratic readings, preventing proper torque reduction.

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🔍 Diagnostic Steps

1. Check Battery & Grounds

Battery voltage ≥ 12.4 V with engine off.

Check ECM/TCM ground connections for corrosion or looseness.

2. Inspect Connectors

Disconnect ECM and TCM connectors.

Look for bent pins, corrosion, or moisture ingress.

3. Check Wiring Continuity

Use a multimeter to check continuity of the torque reduction signal wire between ECM and TCM.

4. Scan Tool Live Data

Observe “Torque Reduction Request” parameter (if available) — verify if it changes during shifting.

5. Clear Code and Test Drive

After repairs, clear the DTC and test drive to see if it reappears.

6. ECM/TCM Reprogramming

If wiring and sensors are fine, visit an authorized Maruti Suzuki service center for module software update or reflash.

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🧰 Possible Fixes

Cause Action

Loose connector / damaged wire Clean, repair or replace connector/harness
Poor grounding Clean and tighten ground points
Faulty sensor Replace faulty sensor (TPS, crank sensor, etc.)
ECM/TCM fault Reflash or replace module
Software issue Dealer reprogramming update

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⚠️ Symptoms You Might Notice

Jerky or delayed gear shifts

Transmission stuck in one gear (limp mode)

Check engine or transmission warning light

Reduced engine power during shifts

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If you can tell me:

Whether your WagonR is AGS (Auto Gear Shift) or 4-speed automatic

And the model year

…I can provide the exact wiring pinout and diagnostic procedure for your vehicle.

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