Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1998 Volvo C70 2D Convertible, AutomaticFACTORY OEM SERVICE PROCEDURE
Checking Communication With ROPS Control Unit
- Turn ignition switch to OFF position. Connect scan tool to DLC. See COMPONENT LOCATIONS . Turn ignition switch to ON position. Try and communicate between scan tool and ABS system. If scan tool can communicate with ABS system, go to next step. If scan tool cannot communicate with ABS system, go to step 5 .
- Turn ignition switch to OFF position. Disconnect scan tool from DLC. Disconnect negative battery cable. Disconnect ROPS control unit. Check ROPS control unit connectors for loose connections or corroded terminals. Check for open in White wire between ROPS control unit connector terminal No. 20 and DLC terminal No. 7. See WIRING DIAGRAMS . Repair as necessary. Voltage at ROPS connector pin (control unit side) should be about 10 volts. If a faulty circuit was found, go to step 8 . If circuit is okay, go to next step.
- Turn ignition switch to ON position. Use DVOM to measure voltage between ground and ROPS control unit connector terminal No. 2 (Orange wire). If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to DTC ROP-429: BATTERY VOLTAGE, SIGNAL LOW permanent fault repair procedure under DIAGNOSTIC TESTS.
- Replace ROPS control unit. See ROPS CONTROL UNIT under REMOVAL & INSTALLATION. After replacement, go to step 8 .
- Check scan tool for proper power and ground circuits to DLC. See scan tool manufacturer's instructions. Repair as necessary. If scan tool is okay, go to next step. If fault was repaired, go to step 8 .
- Check DLC for poor connections, corroded terminals, open or short circuits to ground in wires. See DATA LINK CONNECTORS article in WIRING DIAGRAMS. Repair as necessary. Go to next step.
- Check for short to voltage in White wire between ROPS control unit connector terminal No. 20 and DLC terminal No. 7. See WIRING DIAGRAMS . Repair as necessary. Go to next step.
- Turn ignition switch to OFF position. Reconnect all disconnected components. Connect scan tool to DLC. Turn ignition switch to ON position. Attempt to establish communications with ROPS control unit. If scan tool communicates with ROPS control unit, symptom has been repaired. If scan tool does not communicate with ROPS control unit, fault is still present.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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