Cummins: FAULT CODE: 515 or 516 PID: P091 SPN: 091 FMI: 3 or 4

COOLANT LEVEL SENSOR CIRCUIT
CUMMINS
FAULT CODE: 515 or

516
PID: P091
SPN: 091
FMI: 3 or 4
Coolant Level Sensor Circuit
DESCRIPTION
The coolant level sensor monitors the coolant level within the
coolant system and passes information to the electronic control
module (ECM) through the engine harness.
This is an original equipment manufacturer (OEM)-supplied
component and will vary in sensor location.
- If a shorting plug is used in the coolant level circuit, verify that it is
wired correctly.
- Inspect the wiring harness between the Weather-Pack four-way
connector and the coolant level sensor for damage.
- Make sure the coolant level sensor is located in the middle of the
tank rather than off to one side where the coolant level can change
when the vehicle makes a turn.
Sterling trucks utilize ECM pin A22 for coolant level sensing
through a 2-pin sensor.
COMPONENT LOCATION
The coolant level sensor is located in the radiator top tank or surge
tank.
www.TruckFaultCodes.com
Copywrite 2017
TROUBLESHOOTING STEPS
Step 1A) Turn key switch OFF and disconnect the engine harness from the coolant level sensor. Inspect the
engine harness and the coolant level sensor connector pins for:
• Bent or broken pins
• Pushed back or expanded pins
• Corroded pins
• Moisture in or on the connector
• Missing or damaged seals
No damaged pins?
Go - Go to 1B No - Repair or replace the engine harness or the

coolant level sensor, whichever has damaged pins
Go to 4A
Step 1B) Turn key switch ON and check for fault codes using the diagnostic tool.
Fault Code 515 or 516 remains active?
Yes - Go to 2A No - Clear fault codes

Go to 4A
Step 2A) Turn key switch OFF and disconnect the engine harness from the ECM. Inspect the engine
harness and the ECM connector pins for:
• Bent or broken pins
• Pushed back or expanded pins
• Corroded pins
• Moisture in or on the connector
• Missing or damaged seals
No damaged pins?
Yes - Go to 2B No - Repair or replace the engine harness or the

ECM, whichever has the damaged pins
Go to 4A
Step 2B) Turn key switch OFF and disconnect the engine harness from the ECM. Disconnect the engine
harness from the coolant level sensor. Check for a short circuit to ground. Measure the resistance from pin
37 of the engine harness connector to engine block ground, from pins 19, 27, and 49 of the engine harness
connector to engine block ground.
Copywrite 2017
More than 100k ohms?
Yes - Go to 2C No - Replace the engine harness

Go to 4A
Step 2C) Turn key switch OFF and disconnect the engine harness from the ECM. Disconnect the engine
harness from the coolant level sensor. Check for a short circuit from pin to pin. Measure the resistance from
pin 37 of the engine harness connector to all other pins in the connector, and from pins 49 and 27 of the
engine harness connector to all other pins in the connector.
More than 100k ohms?
Yes - Go to 2D No - Replace the engine harness

Go to 4A
Copywrite 2017
Step 2D) Turn key switch OFF and disconnect the engine harness from the ECM. Disconnect the engine
harness from the coolant level sensor. Check for a short circuit to a voltage source. Measure the voltage
from pin 37 of the engine harness connector to engine block ground, and from pins 27 and 49 of the engine
harness connector to engine block ground.
Less than (+) 1.0 VDC?
Yes - Go to 3A No - Replace the engine harness

Go to 4A
Step 3A) Disconnect the engine harness from the ECM. Turn key switch ON and measure the sensor supply
voltage from the ECM. Measure the voltage from pin 49 of the ECM engine connector to engine block
ground.
(+) 4.5 to 5.25 VDC?
Yes - Go to 4A No - Replace the ECM

Go to 4A
Step 4A) Connect all components and turn key switch ON. Disable the fault code. Start the engine, and let
idle for 1 minute, using the diagnostic tool to verify that Fault Code 515 or 516 is inactive.
Fault Code 515 or 516 inactive?
Yes - Go to 4B No - Return to troubleshooting steps or contact local

Cummins Authorized Repair Location if all steps
have been completed and checked again
Go to 1A
Step 4B) Connect all components, turn key switch ON and clear the inactive fault codes using the diagnostic
tool.
All fault codes cleared?
Yes - Repair is complete No - Troubleshoot any remaining active fault codes

with appropriate troubleshooting steps.
Copywrite 2017
Copywrite 2017

Cummins: FAULT CODE: 515 or 516 PID: P091 SPN: 091 FMI: 3 or 4

Uploaded by

Copyright:

Available Formats

Cummins: FAULT CODE: 515 or 516 PID: P091 SPN: 091 FMI: 3 or 4

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Cummins: FAULT CODE: 515 or 516 PID: P091 SPN: 091 FMI: 3 or 4

Uploaded by

Copyright:

Available Formats

COOLANT LEVEL SENSOR CIRCUIT

FAULT CODE: 515 or

Coolant Level Sensor Circuit

Go - Go to 1B No - Repair or replace the engine harness or the

Fault Code 515 or 516 remains active?

Yes - Go to 2A No - Clear fault codes

Yes - Go to 2B No - Repair or replace the engine harness or the

Yes - Go to 2C No - Replace the engine harness

More than 100k ohms?

Yes - Go to 2D No - Replace the engine harness

Less than (+) 1.0 VDC?

Yes - Go to 3A No - Replace the engine harness

Yes - Go to 4A No - Replace the ECM

Fault Code 515 or 516 inactive?

Yes - Go to 4B No - Return to troubleshooting steps or contact local

Yes - Repair is complete No - Troubleshoot any remaining active fault codes

You might also like