Code
P1177
DAEWOO
P — Powertrain
ETS MOTOR - SHORT /GND 2
Views:
UK: 4
EN: 9
RU: 7
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring shorting to chassis ground
- Corroded, pushed‑out or water‑intruded connector making unintended ground contact
- Internal short in the ETS motor windings or motor driver
- Failed low‑side driver transistor in the ECM/PCM
- Aftermarket equipment or recent repairs that disturbed wiring routing
- Blown or incorrect inline fuse or fusible link affecting circuit protection
Symptoms
- Malfunction indicator lamp (MIL) or check engine light illuminated
- ETS function inoperative or intermittent (motor will not run or respond)
- Possible drivability issues if ETS motor controls throttle/EGR/purge or similar
- Stored freeze frame / freeze data and repeat code after key cycles
- No movement when commanding the motor with a diagnostic tool
What to check
- Read freeze frame and live data with a scan tool; note status of ETS and related PIDs
- Perform visual inspection of ETS motor connector, wiring harness routing and chassis grounding points
- Check for corrosion, water intrusion, pin damage, or pushed‑out terminals at the motor connector
- Backprobe connector with key ON and command motor with scan tool while monitoring voltage
- Measure resistance between motor control pin and chassis ground with connector disconnected
- Check relevant fuses and fusible links for damage or incorrect rating
Signal parameters
- With ignition ON (engine OFF): supply voltage on motor power feed ≈ battery voltage (11.5–14.5 V)
- Control/output pin: expected to be high‑impedance or driven by the ECM (not a steady near 0 V) when idle; if shorted to ground it will read ≈ 0–1 V
- Motor coil resistance (motor disconnected): typical small DC motor/coils often measure in low ohms range (commonly single digits to a few tens of ohms); a near 0 Ω reading indicates a hard short
- When commanded by the ECM: control signal may be PWM; verify presence of switching rather than constant ground
- Continuity test: shorts to chassis ground will show very low resistance (
Diagnostic algorithm
- Record all freeze frame data and any other stored codes. Note whether the code is current or intermittent.
- Visually inspect the ETS motor connector, wiring harness, and ground points for damage, corrosion, pin push‑out, or contact with metal edges. Repair obvious physical damage.
- Disconnect the ETS motor connector. Clear the code, then cycle ignition and see if the code returns. If it does not return with the motor disconnected, suspect wiring or motor.
- With the connector disconnected, measure DC resistance between the motor control pin and chassis ground. A near‑zero reading indicates a short to ground in the motor or harness.
- Check supply voltage at the motor power feed with ignition ON; confirm battery voltage present. Backprobe control pin while commanding the motor with a scan tool to observe expected behavior (PWM or switching).
- If the control pin is shorted to ground with connector disconnected, the short is in the harness or body; trace wiring back toward the ECM, performing continuity and isolation tests and inspecting where the harness contacts metal.
- If motor isolated shows very low coil resistance (shorted) or is confirmed to be the cause, replace the ETS motor and retest.
- If wiring and motor check good, suspect ECM driver fault. Before replacing ECM, confirm driver output at the ECM connector and verify no short on the harness side. Replace ECM only after isolating the failure to the module.
- After repairs, clear codes and perform drive/functional test to confirm code does not return. Reinspect repair if intermittent faults persist.
Likely causes
- Wiring harness damaged where it rubs against body or bracket (short to ground)
- Connector at ETS motor corroded or pin bent, creating ground path
- ETS motor internal shorted coil
- ECM driver transistor shorted to ground (less common)
- Poor ground or secondary aftermarket modification creating unintended ground
Fault status
Status
ETS motor control circuit (channel 2) — short to ground detected by ECM (low voltage/low resistance on motor output).
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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