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.
Inspection Procedure
HINT:
- Although each DTC title says "Coolant Flow Control Valve", these DTCs are related to the water valve.
- CHS stands for Coolant Heat Storage.
HINT:
- If DTCs P1121 and P1150 are detected simultaneously, there may be malfunction in the water valve system.
- If DTC P1121 is detected, coolant passages may be clogged.
- To check the coolant heat storage (CHS) system, the ECM may cause the water pump of the CHS system to operate 5 hours after the power switch has been turned OFF.
- Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
- CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P1121)
- Connect the intelligent tester to the DLC3.
- Turn the power switch ON (IG).
- Turn the tester ON.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
RESULT REFERENCEDisplay (DTC Output) Proceed to P1121 A P1121 and other DTCs B HINT:
If any other codes besides P1121 are output, perform troubleshooting for those DTCs first.
B: Go to DTC CHART
A: Go to Next Step
- PERFORM ACTIVE TEST BY INTELLIGENT TESTER
- Connect the intelligent tester to the DLC3.
- Turn the power switch ON (IG).
- Turn the tester ON.
- Put the engine in inspection mode (see SFI SYSTEM ).
- Start the engine and warm it up.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / WATER FLW VLV3, WATER FLW VLV4 or WATER FLW VLV5.
- Measure the voltage between terminals WBAD and E2 of the ECM connector.
Standard voltage
TESTER CONNECTION SPECIFIED CONDITIONTester Operation Specified Condition "WATER FLW VLV 3" ON Approximately 2.5 V "WATER FLW VLV 4" ON Approximately 3.5 V "WATER FLW VLV 5" ON Approximately 4.5 V
NG: REPLACE WATER W/BRACKET VALVE ASSEMBLY
OK: Go to Next Step
- CHECK COOLING SYSTEM (CHECK FOR CLOGGING IN THE COOLANT SYSTEM)
OK: Coolant passages are not clogged.
NG: REPAIR OR REPLACE COOLING SYSTEM
OK: REPLACE ECM
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.
