Code
P1326
DAEWOO
P — Powertrain
GLOW RELAY - STUCK
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UK: 1
EN: 6
RU: 7
AI status
Completed
Completed
100%
Causes
- Stuck relay contacts (welded or mechanically seized)
- Failed glow relay (internal coil/contact failure)
- Short or open in relay control wiring or power feed
- Faulty relay driver in Engine Control Module (ECM)
- Corroded/loose connectors or blown fuse in glow circuit
- One or more failed/shorted glow plugs causing overcurrent and relay damage
Symptoms
- Glow indicator lamp stays on or does not illuminate as expected
- Hard cold starts or extended cranking time
- Engine stalls after start in cold conditions
- Battery draining when ignition off (if relay stuck closed)
- Possible blown fuses or melted wiring near relay
- DTC present and may set immediately or after a failed glow cycle
What to check
- Scan for related DTCs and read freeze-frame/PCM data (glow requests, battery voltage)
- Visually inspect glow relay, its socket/connections and fuses for corrosion, heat damage or melting
- Verify glow lamp behavior on instrument panel while commanding glow cycle with scan tool
- Backprobe relay control pin with ignition/scan tool commands to confirm ECM control (0V/12V switching)
- Measure supply voltage to relay contact side with key ON (should be battery voltage)
- Check continuity/voltage at glow-plug connector with relay energized and de-energized
Signal parameters
- Relay control signal from ECM: 0 V (off) / ~battery voltage (on) — expect clear switching when commanded
- Relay coil resistance: manufacturer-specific; typically tens to a few hundred ohms (verify with service data)
- Relay contact current capacity: glow circuits commonly draw large current (10–80 A total depending on number/type of glow plugs)
- Preheat duration: commonly a few seconds up to ~30 seconds depending on coolant/air temperature and ECM logic
- Expected voltage at glow plugs when relay energized: near battery voltage (allow voltage drop under high load)
Diagnostic algorithm
- Read and record the P1326 code and any other stored codes. Note freeze-frame data and stored battery voltage.
- Visually inspect the glow relay, fuse(s) and harness for heat damage, corrosion, melted insulation or loose terminals.
- With ignition ON, command a glow cycle using a scan tool and observe lamp, relay click, and voltage at relay coil/control pin. Backprobe the control connector carefully.
- If relay does not switch when commanded but ECM output is present, replace the relay and retest.
- If relay remains energized (stuck closed) even when ECM command is removed, disconnect relay power feed and check if glow plug voltage is removed. If so, replace relay. If voltage remains, isolate wiring short to permanent battery.
- Measure continuity/resistance of glow plugs. Replace any plug with out-of-spec resistance that could overload the relay.
- Measure current draw of the glow circuit with clamp meter during preheat. Excessive current suggests shorted/failed glow plug(s) or poor wiring.
- If relay and wiring check good but ECM is not commanding correctly (no switching signal or stuck output), verify ECM ground and power. If ECM output driver is suspected, consult manufacturer procedures — ECM replacement or repair may be required.
- Clear codes and perform multiple cold-start cycles to confirm repair. Re-scan and verify no reoccurrence.
Likely causes
- Relay contacts welded closed from high current or heat
- Relay coil stuck or shorted so ECM cannot change state
- Battery voltage feeding relay is shorted to ground or to permanent power
- Damaged connector or burnt wiring at relay or glow-plug harness
- ECM output driver fault (less common than relay failure)
Fault status
Status
Glow relay stuck — relay contacts are not switching as commanded by the ECM, affecting glow-plug circuit operation; code stored by ECU.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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