Code
P1389
PONTIAC
P — Powertrain
No Auto Shutdown ASD Relay Output Voltage At PCM
AI status
Completed
Completed
100%
Causes
- Blown ASD relay fuse or fusible link
- ASD relay failed (open coil or contacts)
- Open, shorted or corroded wiring between PCM and ASD relay
- Poor or missing ground at ASD relay or PCM
- PCM driver transistor or internal circuitry fault
- Poor connector contact at PCM or relay socket
Symptoms
- Engine cranks but will not start
- No spark or no injector pulse
- No fuel pump operation (if fed through ASD)
- Malfunction Indicator Lamp (MIL) may be illuminated
- Intermittent no-start or stalling
What to check
- Verify battery voltage is normal (12.4–12.8V resting) before tests
- Visually inspect ASD relay, fuse(s), relay socket and wiring for damage or corrosion
- Check for additional stored DTCs that indicate related circuits
- Measure voltage at relay coil supply terminal with key ON (should be battery voltage)
- Verify continuity between PCM ASD control pin and relay coil terminal
- Backprobe PCM ASD output: observe active state during crank/run
Signal parameters
- ASD control circuit type: typically PCM switched ground for ASD relay coil
- Expected at PCM ASD output pin when active: ~0.0–0.3 V (grounded)
- Expected at PCM ASD output pin when inactive: ~battery voltage (~11–14 V) via relay coil supply or pull-up
- Continuity: low resistance (a few ohms) between PCM ASD pin and relay coil terminal
- No-load relay coil resistance: typically tens of ohms (consult vehicle-specific spec)
Diagnostic algorithm
- Safety: disconnect battery only if instructed by service manual for PCM connector work. Work in a safe, ventilated area.
- Retrieve freeze frame and full DTC list. Note conditions when P1389 set (key position, crank/run status).
- Visually inspect ASD relay, fuse(s) and relay socket. Replace blown fuses and reseat or swap relay with known-good same-type relay.
- With key ON (engine OFF), measure battery voltage at the ASD relay coil supply terminal. If no battery voltage, trace and repair fuse/ignition feed to relay.
- Backprobe the PCM ASD control pin. With key ON and during cranking, the PCM should pull the ASD control to ground (near 0V) to energize the relay. If PCM does not pull low, proceed to step 7.
- If PCM does pull low but relay does not energize, check continuity from PCM pin to relay coil terminal and check coil resistance. Repair wiring or replace relay as needed.
- If wiring and relay are good but PCM never drives the circuit, check for shorts to voltage or ground on the control circuit. Repair any wiring faults.
- If wiring and external components check good and no drive from PCM, perform PCM connector/terminal repair as per manual. Replace PCM only after verifying external circuit integrity and following manufacturer reprogramming/calibration procedures.
- Clear codes and perform a functional test (crank/run) to confirm repair. Monitor for recurrence and re-scan for additional codes.
Likely causes
- Faulty ASD relay
- Broken or disconnected wire in ASD control circuit
- Blown fuse supplying ASD relay coil or contacts
- Damaged PCM output pin or internal driver
- Corroded relay socket or PCM connector terminal
Fault status
Status
PCM reports no expected ASD relay output voltage on the ASD circuit; ASD relay not being driven or ASD output not present at PCM.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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