Code
P1325
DAEWOO
P — Powertrain
GLOW RELAY - PERFORMANCE MAL
Views:
UK: 2
EN: 7
RU: 3
AI status
Completed
Completed
100%
Causes
- Failed or intermittent glow relay
- Blown fuse or fusible link for glow/relay circuit
- Open/shorted wiring or poor connector continuity between relay, glow plugs, and ECM
- Corroded or loose ground(s)
- Weak or discharged battery / low supply voltage
- Faulty glow plugs causing abnormal current draw
Symptoms
- Glow/plugs indicator lamp behaves abnormally (won't extinguish or won't illuminate)
- Long cranking time or difficult cold starts
- Rough idle after cold start
- Reduced starting performance in cold weather
- DTC P1325 stored; possible related engine warning lamp
What to check
- Visual inspection of relay, fuse, wiring harness and connectors for damage, corrosion, loose pins
- Check battery voltage (engine off and during crank) — must be healthy
- Check glow relay fuse continuity and replace if blown
- Listen/feel for relay click when ignition key moved to preheat position
- Backprobe relay coil and switch terminals to verify control and supply voltages
- Measure voltage at glow plug terminals during preheat request
Signal parameters
- Battery supply to relay: approx. 12 V (nominal) with key ON/preheat
- Relay control signal from ECM: switched ground or +12 V while preheating (verify with scan tool)
- Voltage at glow plug output when activated: near battery voltage (allowing for wiring/connector drop)
- Glow plug resistance (cold): typically low ohms per plug — check OEM spec for exact values
- Relay coil resistance: verify against OEM spec; open or shorted coil indicates relay failure
- Current draw when relay active: elevated (multiple amps) — abnormal low or zero current indicates open circuit; abnormally high indicates shorted glow plug or wiring
Diagnostic algorithm
- Retrieve freeze frame and live data with a scanner to confirm P1325 and observe glow control behavior during a preheat request.
- Visually inspect glow relay, connector, fuses and wiring for corrosion, damage or loose connections. Repair as needed.
- With engine off, check battery voltage and battery condition. Charge or replace battery if voltage is low.
- Check fuse(s) supplying the glow relay for continuity; replace any blown fuses.
- With ignition in preheat position (follow vehicle service manual), verify relay activation (listen for click). Backprobe relay coil terminals to confirm presence of supply voltage and control signal from the ECM.
- Measure voltage at glow plug output terminal(s) while relay is commanded ON. If no voltage, bench-test or swap the relay with a known-good relay of the same type.
- Measure individual glow plug resistances and compare to OEM spec. Replace any open or shorted glow plugs.
- Measure current draw of the glow plug circuit when activated. Excessive or no current indicates short/open or bad plug/connector.
- Inspect and clean ground points and connectors for the glow circuit. Repair wiring harness as required (repair/replace damaged connectors/wires).
- If wiring, relay and plugs check good but fault persists, verify ECM output driver with manufacturer-specific procedures; replace ECM only after confirming peripheral components are good.
- Clear DTCs, perform a controlled preheat/test cycle and confirm the fault does not return before completing repair.
Likely causes
- Failed glow relay or relay contacts sticking
- Blown fuse or poor power supply to relay
- Wiring/connector corrosion or loose ground at relay/glow plug bank
Fault status
Status
Glow relay performance malfunction — ECM detected incorrect operation of the glow relay/circuit controlling glow plug preheating. May cause hard cold starting and extended cranking times.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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