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Home >> Suzuki >> 2002 >> Aerio GS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0480: Radiator Cooling Fan Control Circuit Malfunction >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

CAUTION: While performing this test procedure, DO NOT let engine overheat.
NOTE: For better performance and results of this diagnostic procedure, usage of appropriate wiring diagram is recommended. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
NOTE: Perform all voltage and resistance tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use an ohmmeter to isolate wiring harness shorts or opens.
  1. If engine system check has been performed, go to next step. If engine system check has not been performed, perform TEST D: ENGINE SYSTEM CHECK  under SYSTEM TESTS then go to next step.
  2. Turn ignition switch to LOCK position. Disconnect Radiator Fan Control Relay No. 1 (RFCR-1) from engine compartment fuse/relay box. See Figure. Turn ignition switch to ON position. Measure voltage between ground and RFCR-1 connector E08 terminals No. 2 (Blue/White wire) and No. 3 (Black/White wire). See Fig 1. If voltage is 10-14 volts, go to next step. If voltage is not 10-14 volts, repair open circuit in Blue/White wire and/or Black/White wire between RFCR-1 and fuse relay/box. After repair, repeat DTC CONFIRMATION TEST .
  3. Turn ignition switch to LOCK position. Reconnect RFCR-1 to fuse/relay box. Locate ECM 35-pin harness connector G04. See Figure. Turn ignition switch to ON position. Backprobe and measure voltage between ground and ECM harness connector G04 terminal No. 3 (Brown wire). See Figure. If voltage is not 10-14 volts, go to next step. If voltage is 10-14 volts, go to step  7.
  4. Turn ignition switch to LOCK position. Disconnect ECM harness connector G04. Disconnect RFCR-1 from fuse/relay box. Measure resistance between ground and ECM harness connector G04 terminal No. 3 (Brown wire). See Figure. If resistance is infinity, go to next step. If any resistance is found, repair short to ground in Brown wire between ECM and RFCR-1. After repair, repeat DTC CONFIRMATION TEST .
  5. Turn ignition switch to ON position. Measure voltage between ground and ECM harness connector G04 terminal No. 3 (Brown wire). See Figure. If voltage is zero volts, go to next step. If any voltage is found, repair short to voltage in Brown wire between ECM and RFCR-1. After repair, repeat DTC CONFIRMATION TEST .
  6. Turn ignition switch to LOCK position. Perform RFCR-1 component test as follow:
    • Check continuity between radiator fan control relay terminals "C" and "B". See Fig 2. If continuity is not found, go to next step. If continuity is found, replace radiator fan control relay and repeat DTC CONFIRMATION TEST .
    • Connect fused jumper wire between battery (+) and radiator fan control relay terminal "B", also connect another jumper wire between battery (-) and radiator fan control relay terminal "A". See Fig 2. Check continuity between radiator fan control relay terminals "C" and "D". See Fig 2. If continuity is not found, replace radiator fan control relay and repeat DTC CONFIRMATION TEST . If continuity is not found, repair open circuit in Brown wire between ECM and radiator fan control relay. After repair, repeat DTC CONFIRMATION TEST .
  7. Reconnect G04 harness connector to ECM and radiator fan control relays to fuse/relay box. Start engine and allow it to idle until reaches 207°F (97°C). Backprobe and measure voltage between ground and ECM harness connector G04 terminals No. 3 (Brown wire). See Figure. If voltage is less than 1.5 volts, go to next step. If voltage is 1.5 volts or more, replace ECM. See ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, repeat DTC CONFIRMATION TEST .
  8. Turn ignition switch to LOCK position. Disconnect Radiator Fan Control Relay No. 2 (RFCR-2) and Radiator Fan Control Relay No. 3 (RFCR-3) from engine compartment fuse/relay box, located near battery. See Figure. Start engine and allow it to idle until reaches 207°F (97°C). Measure voltage between ground and RFCR-2 connector E09 terminal No. 3 (Blue/Red wire) and RFCR-3 connector E11 terminal No. 3 (Blue/Red wire). See Fig 1. If voltage is 10-14 volts, go to next step. If voltage is less than 10-14 volts, repair open or short circuit in Blue/Red wire between cooling fan motor, RFCR-2 and RFCR-3. After repair, repeat DTC CONFIRMATION TEST .
  9. Turn ignition switch to LOCK position. Reconnect RFCR-2 to fuse/relay box. Disconnect ECM harness connector G04. Turn ignition switch to ON position. Measure voltage between ground and ECM harness connector G04 terminal No. 34 (Green/Red wire). See Figure. If voltage is 10-14 volts, go to next step. If voltage is not 10-14 volts, go to step  11.
  10. Turn ignition switch to LOCK position. Disconnect RFCR-2 from fuse/relay box. Reconnect RFCR-3 to fuse/relay box. Turn ignition switch to ON position. Measure voltage between ground and ECM harness connector G04 terminal No. 34 (Green/Red wire). See Figure. If voltage is not 10-14 volts, go to next step. If voltage is 10-14 volts, go to step  14.
  11. Turn ignition switch to LOCK position. Disconnect RFCR-3 from fuse/relay box. Measure resistance between ground and ECM harness connector G04 terminal No. 34 (Green/Red wire). See Figure. If resistance is infinity, go to next step. If any resistance is found, repair short to ground circuit in Green/Red wire between ECM, RFCR-2 and RFCR-3. After repair, repeat DTC CONFIRMATION TEST .
  12. Turn ignition switch to ON position. Measure voltage between ground and ECM harness connector G04 terminal No. 34 (Green/Red wire). See Figure. If voltage is zero volts, go to next step. If any voltage is found, repair short to voltage in Green/Red wire between ECM, RFCR-2 and RFCR-3. After repair, repeat DTC CONFIRMATION TEST .
  13. Turn ignition switch to LOCK position. Perform RFCR-2 and RFCR-3 component test as follows:
    • Check continuity between radiator fan control relay terminals "C" and "B". See Fig 2. If continuity is not found, go to next step. If continuity is found, replace radiator fan control relay and repeat DTC CONFIRMATION TEST .
    • Connect fused jumper wire between battery (+) and radiator fan control relay terminal "B", also connect another jumper wire between battery (-) and radiator fan control relay terminal "A". See Fig 2. Check continuity between radiator fan control relay terminals "C" and "D". See Fig 2. If continuity is not found, replace radiator fan control relay and repeat DTC CONFIRMATION TEST . If continuity is not found, repair open circuit in Green/Red wire between ECM, RFCR-2 and RFCR-3. After repair, repeat DTC CONFIRMATION TEST .
  14. Reconnect G04 harness connector to ECM and radiator fan control relays to fuse/relay box. Start engine and allow it to idle until reaches 207°F (97°C). Backprobe and measure voltage between ground and ECM harness connector G04 terminals No. 34 (Green/Red wire). See Figure. If voltage is 1.5 volts or more, replace ECM. See ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, repeat DTC CONFIRMATION TEST . If voltage is less than 1.5 volts, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If no intermittent problem is found, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST .
Fig 1: Identifying Radiator Fan Control Relay/Box Connector E08 & E09 Terminals
G00232472Courtesy of SUZUKI OF AMERICA CORP.
Fig 2: Testing Radiator Cooling Fan Relay No. 1, 2 & 3
G00232471Courtesy of SUZUKI OF AMERICA CORP.
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