Code
P1304
DAEWOO
P — Powertrain
PHASE SNSR
AI status
Completed
Completed
100%
Causes
- Failed or degraded phase (camshaft) position sensor
- Damaged wiring harness, broken wires or poor connector at sensor
- Corroded or loose connector pins
- Damaged reluctor/target wheel or timing components
- Incorrect cam/crank timing (mechanical timing off)
- Intermittent short to power or ground on sensor circuit
Symptoms
- Check Engine Light (MIL) illuminated
- Engine may be hard to start or will not start
- Rough idle, misfire or hesitation under load
- Reduced engine power or limp-home mode
- Stalling at idle or during low-speed operation
- Poor fuel economy or increased emissions
What to check
- Read freeze-frame and freeze PIDs with a scan tool; note engine speed and conditions when code set
- Visual inspection of phase sensor, connector and wiring for damage, corrosion, oil contamination or loose pins
- Wiggle-test wiring and connectors while monitoring live cam/crank signals for intermittent dropouts
- Check for related codes (cam/crank position codes) and compare cam vs crank correlation on a lab scope or OEM scan tool
- Measure reference power and ground at the sensor connector with key on
- Measure sensor output (voltage/waveform) during cranking and running using an oscilloscope or multimeter (as applicable)
Signal parameters
- Hall-type cam sensor: 0 to ~5 V square wave; transitions referenced to cam position; frequency proportional to engine speed
- Variable-reluctance (VR) cam sensor: AC waveform amplitude increases with engine rpm; may appear ~0.1–12 VAC depending on sensor and rpm
- One or more pulses per cam revolution (cam sensor usually produces half the crank pulses; exact pulse count is vehicle-specific)
- Signal must be present and consistent during cranking and while running; no long dropouts or distorted waveforms
- Reference supply (if used): battery or switched 5 V reference and a stable ground
Diagnostic algorithm
- Retrieve and record all stored codes and freeze-frame data. Clear codes and attempt to re-run to capture recurrence.
- Perform a thorough visual inspection of the cam/phase sensor, connector, wiring harness routing and target wheel; repair obvious damage.
- Verify sensor supply and ground at the connector with ignition ON (reference voltage or battery voltage as specified).
- Probe the sensor signal circuit while cranking and running: use an oscilloscope for best diagnosis; verify correct waveform shape, amplitude and timing relation to crank sensor.
- If signal is missing or abnormal, backprobe and wiggle wiring to locate intermittent faults; repair broken wires, corroded pins or poor grounds.
- Check cam/crank correlation using a scan tool: confirm cam angle vs crank angle is within factory tolerance; if not, inspect timing belt/chain, tensioner and sprockets.
- If wiring and mechanical timing are good but signal still fails, replace the phase (camshaft) sensor with a known-good unit and retest.
- If replacement sensor does not restore proper signal, check ECM input for shorts/opens and consider ECM bench testing or replacement as a last resort.
- After repairs, clear codes and perform a road/test drive and re-scan to confirm the fault does not return.
Likely causes
- Sensor failed due to age or contamination (oil/metal debris)
- Connector pins corroded or pushed out causing intermittent contact
- Wire chafing causing intermittent short to chassis ground or battery
- Reluctor tooth missing or damaged (after cam sprocket or sensor area)
- Timing belt/chain jumped a tooth causing signal mismatch
- ECM pin damaged or internal electronics degraded
Fault status
Status
Phase (camshaft) sensor circuit malfunction — ECM not detecting a valid cam/phase signal or detects inconsistent signal.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Repair manuals
Manual library for DAEWOO
75
Browse 75 DAEWOO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
DAEWOO
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DAEWOO: 2001
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Leganza
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DAEWOO: 2000
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Leganza
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DAEWOO: 1999
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Lanos
- S, 2D Hatchback, Automatic
- S, 2D Hatchback, Standard
- S, 4D Sedan, Automatic
- S, 4D Sedan, Standard
- SE, 2D Hatchback, Automatic
- SE, 2D Hatchback, Standard
- SE, 4D Sedan, Automatic
- SE, 4D Sedan, Standard
- SX, 2D Hatchback, Automatic
- SX, 2D Hatchback, Standard
- SX, 4D Sedan, Automatic
- SX, 4D Sedan, Standard
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Leganza
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Nubira
- CDX, 4D Hatchback, Automatic
- CDX, 4D Hatchback, Standard
- CDX, 4D Sedan, Automatic
- CDX, 4D Sedan, Standard
- CDX, 4D Wagon, Automatic
- CDX, 4D Wagon, Standard
- SX, 4D Hatchback, Automatic
- SX, 4D Hatchback, Standard
- SX, 4D Sedan, Automatic
- SX, 4D Sedan, Standard
- SX, 4D Wagon, Automatic
- SX, 4D Wagon, Standard
-
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