Wait to Start Indicator Circuit Diagnosis (K07UFM)
Wait to Start Indicator Circuit Diagnosis (LC8\K07\UFM)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Circuit/System Description
The LPG control module supplies voltage to the wait to start indicator during the purge cycle. The purge cycle is enabled during the first 5-8 seconds of initial ignition ON. The LPG control module will not enable purge mode until the vehicle has been powered down for at least 2 minutes. If the LPG control module detects a fault within the input or control circuits of the system, the wait to start indicator will be commanded to flash the appropriate code.
Diagnostic Fault Information
Conditions for Running the DTC
Ignition ON for greater than 40 s.
Conditions for Setting the DTC
All faults must be present for at least 1.25 s.
DTC 1
Battery input voltage is greater than 27.6 V.
DTC 2
Battery input voltage is less than 0.4 V.
DTC 3
Fuel pressure input is greater than 3440 kPa (499 psi).
DTC 4
Fuel pressure input is less than -337 kPa (-49 psi).
DTC 5
Fuel temperature input is greater than 254°C (489°F).
DTC 6
Fuel temperature input is less than -254°C (-425°F).
DTC 7
LPG fuel tank bypass control circuit open/short
DTC 8
Vacuum pump control circuit open/short
DTC 10
5 V reference voltage output is greater than 5.4 v.
DTC 11
Internal voltage transducer error
DTC 12
Internal voltage transducer error
DTC 13
5 V reference voltage output is less than 4.6 V.
Action Taken When the DTC Sets
The wait to start indicator will flash the appropriate code when Ignition is ON.
Conditions for Clearing the DTC
* Cycle the ignition 6 times within 10 seconds
or
* Disconnect the LPG control module
or
* A repaired fault will clear automatically
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Circuit/System Verification
1. Ignition OFF.
2. Verify the Wait to Start indicator is not activated.
• If the Wait to Start indicator is activated
Refer to Circuit/System Testing
• If the Wait to Start indicator is not activated
3. Ignition ON.
4. Verify the Wait to Start indicator activates for the initial 5-8 seconds of ignition ON and turns OFF.
• If the Wait to Start indicator does not activate or remains ON
Refer to Circuit/System Testing
• If the Wait to Start indicator flashes
Refer to the appropriate DTC Testing.
• If the Wait to Start indicator activates for 5-8 seconds and turns OFF
5. All OK
Circuit/System Testing
No DTCs Present
1. Ignition OFF, disconnect the wait to start indicator relay.
2. Verify a test lamp illuminates between the B+ circuit terminal 86 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance,
3. Test for greater than 2 ohms between the control circuit terminal 85 and ground.
• If less than 2 ohms, repair the short to ground on the circuit.
• If greater than 2 ohms.
4. Test for greater than 2 ohms between the component control circuit terminal 87 and ground.
• If less than 2 ohms, repair the short to ground on the circuit.
• If greater than 2 ohms, replace the wait to start indicator relay.
• If the test lamp illuminates
3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If the test lamp illuminates
4. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
5. Verify the test lamp turns ON for 5-8 seconds after initial ignition ON and then turns OFF.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the LPG control module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF.
4. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the LPG control module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the LPG control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the LPG control module.
• If the test lamp turns ON and OFF
6. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the wait to start indicator. It may take up to 2 minutes for all vehicle systems to power down.
7. Test for less than 10 ohms between the wait to start indicator ground circuit terminal B and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
8. Connect the harness connector at the wait to start indicator.
9. Ignition ON, connect a 3 A fused jumper wire between the B+ circuit terminal 30 and the component control circuit terminal 87.
10. Verify the wait to start indicator is activated.
• If the wait to start indicator does not activate
1. Ignition OFF.
2. Test for less than 2 ohms in the component control circuit terminal 87 end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the wait to start indicator.
• If the wait to start indicator activates
11. Test or replace the wait to start indicator relay.
DTC 1 or 2
1. Ignition OFF, disconnect the harness connector at the LPG control module.
2. Test for less than 10 ohms between the LPG control module ground circuit terminal 14 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Test for 0.4-27.6 V between the LPG control module voltage circuit terminal 16 and ground.
• If less than 0.4 V
Repair the open/high resistance in the circuit.
• If greater than 27.6 V
Refer to Charging System Test Testing and Inspection
• If between 0.4-27.6 V
Test or replace the LPG control module.
DTC 3, 4, 5, 6, 10, 11, 12, or 13
1. Ignition OFF, disconnect the harness connector at the B190 LPG pressure and temperature sensor, Ignition ON.
2. Test for less than 18 ohms between the B190 LPG pressure and temperature sensor ground circuit terminal 1 and ground.
• If 18 ohms or greater
1. Ignition OFF, disconnect the LPG control module.
2. Test for less than 2 ohms between the B190 LPG pressure and temperature sensor ground circuit terminal 1 and the LPG control module connector terminal 1.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the LPG control module.
• If less than 18 ohms
3. Test for 4.5-5.5 V between the B190 LPG pressure and temperature sensor 5 V reference circuit terminal 4 and ground.
• If less than 4.5 V
1. Disconnect the LPG control module harness connector.
2. Test for less than 2 ohms between the B190 LPG pressure and temperature sensor 5 V reference circuit terminal 4 and the LPG control module connector terminal 18.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the LPG control module.
• If greater than 5.5 V
1. Disconnect the LPG control module harness connector. Ignition ON.
2. Test for less than 1 V between the B190 LPG pressure and temperature sensor 5 V reference circuit terminal 4 and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less than 1 V, test or replace the LPG control module.
• If between 4.5-5.5 V
4. Test for 4.5-5.5 V between the B190 LPG pressure and temperature sensor temperature signal circuit terminal 3 and ground.
• If less than 4.5 V
1. Disconnect the LPG control module harness connector.
2. Test for less than 2 ohms between the B190 LPG pressure and temperature sensor temperature signal circuit terminal 3 and the LPG control module connector terminal 17.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the LPG control module.
• If greater than 5.5 V
1. Disconnect the LPG control module harness connector. Ignition ON.
2. Test for less than 1 V between the B190 LPG pressure and temperature sensor temperature signal circuit terminal 3 and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less than 1 V, test or replace the LPG control module.
• If between 4.5-5.5 V
5. Test for 4.5-5.5 V between the B190 LPG pressure and temperature sensor fuel pressure signal circuit terminal 2 and ground.
• If less than 4.5 V
1. Disconnect the LPG control module harness connector.
2. Test for less than 2 ohms between the B190 LPG pressure and temperature sensor fuel pressure signal circuit terminal 2 and the LPG control module connector terminal 5.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the LPG control module.
• If greater than 5.5 V
1. Disconnect the LPG control module harness connector. Ignition ON.
2. Test for less than 1 V between the B190 LPG pressure and temperature sensor fuel pressure signal circuit terminal 2 and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less than 1 V, test or replace the LPG control module.
• If between 4.5-5.5 V
6. Test or replace the B190 LPG pressure and temperature sensor.
DTC 7
1. Ignition OFF, disconnect the harness connector at the LPG bypass relay.
2. Verify a test lamp illuminates between the LPG bypass relay B+ circuit terminal 86 and ground.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does illuminates
3. Verify that a test lamp does not illuminate between the LPG bypass relay B+ circuit terminal 86 and the control circuit terminal 85.
• If the test lamp illuminates
1. Ignition OFF, disconnect the harness connector at the LPG control module.
2. Test for infinite resistance between the control circuit terminal 85 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the LPG control module.
• If the test lamp does not illuminate
4. Remove the test lamp. Reconnect the LPG bypass relay connector.
5. Install a 10 A fused jumper between the LPG control module LPG bypass relay control circuit terminal 22 and ground.
6. Verify the LPG bypass relay is active.
• If the LPG bypass relay does not activate
1. Disconnect the harness connector at the LPG bypass relay, Ignition ON.
2. Test for less than 1 V between the LPG bypass relay control circuit terminal 85 and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less the 1 V
3. Test for less than 2 ohms between the LPG bypass relay control circuit terminal 85 and the LPG control module connector terminal 22.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the LPG bypass relay.
• If the LPG bypass relay activates
7. Test or replace the LPG control module.
DTC 8
1. Ignition OFF, disconnect the harness connector at the vacuum pump.
2. Verify a test lamp illuminates between the vacuum pump B+ circuit terminal A and ground.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does illuminates
3. Verify that a test lamp does not illuminate between the vacuum pump B+ circuit terminal A and the control circuit terminal B.
• If the test lamp illuminates
1. Ignition OFF, disconnect the harness connector at the LPG control module.
2. Test for infinite resistance between the control circuit terminal B and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the LPG control module.
• If the test lamp does not illuminate
4. Remove the test lamp. Reconnect the vacuum pump connector.
5. Install a 10 A fused jumper between the LPG control module vacuum pump control circuit terminal 24 and ground.
6. Verify the vacuum pump is operating.
• If the vacuum pump does not operate
1. Disconnect the harness connector at the vacuum pump, Ignition ON.
2. Test for less than 1 V between the vacuum pump control circuit terminal B and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less the 1 V
3. Test for less than 2 ohms between the vacuum pump control circuit terminal B and the LPG control module connector terminal 24.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, test or replace the vacuum pump.
• If the vacuum pump operates
7. Test or replace the LPG control module.
Component Testing
1. Ignition OFF, disconnect the wait to start indicator relay.
2. Test for 70-110 ohms between terminal 85 and 86.
• If not within the specified range
Replace the wait to start indicator relay.
• If between 70-110 ohms
3. Test for infinite resistance between the terminals listed below:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If less than infinite resistance
Replace the wait to start indicator relay
• If infinite resistance
4. Connect a 3 A fused jumper wire between relay terminal 86 and B+. Connect a jumper wire between relay terminal 85 and ground. Test for less than 2 ohms between terminals 30 and 87.
• If 2 ohms of greater
Replace the wait to start indicator relay
• If less than 2 ohms
5. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Fuel Pump Flow Control Module Replacement Service and Repair
* LPG Fuel Pressure and Temperature Sensor Replacement (3 Tank) Service and Repair
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Evaporative Emission System Vacuum Leak Detection Pump Replacement (LPG 3 Tank) Service and Repair