Information Center: Overview Mercury Sable V

Principles of Operation

Note. The smart junction box (SJB) is also known as the generic electronic module (GEM).

Note. Whenever a network message is suspected as missing and confirmed by a missing message DTC (U-code), it is important to look for other symptoms that may also be present in the instrument cluster (IC) and throughout the vehicle. Once a DTC is set in the instrument cluster (IC), it may be helpful to review the complete message list available in MODULE COMMUNICATIONS NETWORK article to see what other modules also rely on the same message and run the self-test for those modules. If the message is missing from other modules, the same DTC may also be set in those modules. Confirmation of missing messages common to multiple modules may indicate that the originating module is the source of the concern or the communication network may be experiencing some problems.

The instrument cluster (IC) utilizes a microprocessor to control the gauge, indicator, message center and warning chime functions. Data is sent to the instrument cluster (IC) over the medium speed controller area network (MS-CAN) and the high speed controller area network (HS-CAN) bus lines and through hardwired circuitry from individual components. The instrument cluster (IC) uses each input to output an action to the gauges or indicators. If a required message is missing or invalid for less than 5 seconds, the gauge or indicator that requires the message remains at the last commanded state based upon the last known good message. For example, if the brake status message is missing for less than 5 seconds and the brake warning indicator was ON, the indicator remains in the ON state until the next good message is received. If the message remains missing or invalid for greater than 5 seconds, the instrument cluster (IC) sets a U-code DTC and the output becomes a default action for the indicator or gauge. Each indicator or gauge utilizes a different default strategy depending on the nature of the indication. Refer to the normal operation descriptions located before each individual pinpoint test for further description of the default action specific to each indicator or gauge. If the messaged input to the cluster returns at any time, the normal function of the gauge or indicator resumes.

It is very important to understand

1. where the input originates.
2. all the information necessary in order for a feature to operate.
3. which module(s) receive(s) the input or command message.
4. does the module which received the input control the output of the feature, or does it output a message over the communication network to another module.
5. which module controls the output of the feature.

Normal Operation

With the ignition switch in the START or RUN position, the instrument cluster (IC) receives voltage from the smart junction box (SJB) through circuit CBP29 (WH/VT). With the ignition switch in the OFF position, the instrument cluster (IC) receives its keep-alive voltage from the SJB through circuit SBP26 (YE/RD). The instrument cluster (IC) grounding is through circuit GD111 (BK/BU). The instrument cluster (IC) sets DTC U2472 in continuous memory and on-demand if the RUN/START input, circuit CBP29 (WH/VT), is open or if the SJB fuse 29 (5A) has failed.

This pinpoint test is intended to diagnose the following

1. Fuse(s)
2. Wiring, terminals or connectors
3. Instrument cluster (IC)

The fuel pump module is hardwired to the instrument cluster (IC) between the signal circuit VMC11 (YE/VT) and the signal return circuit RMC32 (GN/BU), which is grounded internally within the instrument cluster (IC). The fuel level sensor card is a variable resistor attached to the fuel pump module that ranges from 180 ohms ± 4 ohms at empty (E) and 10 ohms ± 2 ohms at full (F). The instrument cluster (IC) provides a reference voltage to the fuel pump module on circuit VMC11 (YE/VT). As the fuel level changes, a float actuates a variable resistor on the fuel level sensor card and raises or lowers the fuel level signal voltage depending on the resistance of the fuel level sensor. The instrument cluster (IC) monitors the changes in voltage and commands the fuel gauge with a corresponding movement of the pointer.

The instrument cluster (IC) uses 4 different operating modes to calculate the fuel level

1. Anti-slosh (default mode)
2. Key OFF fueling
3. Key ON fueling
4. Recovery

After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.

The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).

The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met

1. The key must be in the OFF position when refueling the vehicle.
2. At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
3. The instrument cluster (IC) must receive a valid key ON fuel sender reading within 1 second of the key being put into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 10 ohms ± 2 ohms and 180 ohms ± 4 ohms.

If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.

The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires the following conditions be met

1. The transmission is in PARK (P).
2. The key is in the RUN position.
3. At least 15% of the vehicle's fuel capacity must be added to the fuel tank.

In key ON fueling mode, a 30-second timer activates after the transmission is put into the PARK (P) position (automatic transmissions) or when the parking brake is applied (manual transmissions). When the 30-second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transmission is shifted out of PARK (P) or the parking brake is released, the fuel gauge strategy reverts to the anti-slosh mode. The key ON fueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.

Recovery mode is incorporated into the instrument cluster (IC) strategy to recover from a missing fuel level input after a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met

1. The instrument cluster (IC) is in the anti-slosh (default) mode.
2. The actual fuel level in the tank is greater than what is being displayed by the fuel gauge.

INSTRUMENT CLUSTER (IC) DTCS

PCM DTCS

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Fuel pump module
3. Fuel level sensor card
4. Fuel tank
5. Instrument cluster (IC)

The fuel tank is a saddle tank design with variable resistance senders, driven by floats, that provide resistances related to fuel height in each side to the instrument cluster (IC). The fuel level is determined using variable resistance fuel sensor units, with an approximate resistance range between 180 ohms ± 4 ohms at empty (E) and 10 ohms ± 2 ohms at full (F). The instrument cluster (IC) sends a reference voltage to the fuel pump module through circuit VMC11 (YE/VT) and the fuel level sensor through circuit VMC23 (GN/OG) and receives the signal returns through circuit RMC32 (GN/BU) from the fuel pump module and RMC33 (WH/VT) from the fuel level sensor. As the fuel level changes, a float actuates a variable resistor on the fuel pump module and fuel level sensor and raises or lowers the fuel level signal voltage depending on the resistance of the fuel level sensor card. The instrument cluster (IC) monitors the changes in voltage from both senders and commands the fuel gauge with a corresponding movement of the pointer. If the instrument cluster (IC) detects the fuel level sensor circuitry is open, the fuel gauge defaults to the fuel pump module value only and the fuel gauge indicates E to 1/2 tank. If the instrument cluster (IC) detects fuel pump module circuitry is open, the fuel gauge defaults to the empty position.

The instrument cluster (IC) uses 4 different operating modes to calculate the fuel level

1. Anti-slosh (default mode)
2. Key OFF fueling
3. Key ON fueling
4. Recovery

After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.

The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).

The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met

1. The key must be in the OFF position when refueling the vehicle.
2. At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
3. The instrument cluster (IC) must receive a valid key ON fuel sender reading within 1 second of the key being put into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 10 ohms ± 2 ohms and 180 ohms ± 4 ohms.

If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.

The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires the following conditions be met

1. The transmission is in PARK (P).
2. The key is in the RUN position.
3. At least 15% of the vehicle's fuel capacity must be added to the fuel tank.

In key ON fueling mode, a 30-second timer activates after the transmission is put into the PARK (P) position (automatic transmissions) or when the parking brake is applied (manual transmissions). When the 30-second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transmission is shifted out of PARK (P) or the parking brake is released, the fuel gauge strategy reverts to the anti-slosh mode. The key ON fueling mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.

Recovery mode is incorporated into the instrument cluster (IC) strategy to recover from a missing fuel level input after a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met

1. The instrument cluster (IC) is in the anti-slosh (default) mode.
2. The actual fuel level in the tank is greater than what is being displayed by the fuel gauge.

INSTRUMENT CLUSTER (IC) DTCS

PCM DTCS

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Fuel tank transfer tube
3. Fuel pump module
4. Fuel level sensor
5. Fuel level sensor card
6. Fuel lines
7. Fuel tank
8. Instrument cluster (IC)

The PCM uses the cylinder head temperature (CHT) sensor to measure the engine coolant temperature. The instrument cluster (IC) receives the engine coolant temperature data from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster (IC) monitors the engine coolant temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

If the engine coolant temperature data is missing for 5 seconds or less or if instrument cluster (IC) receives invalid engine coolant temperature data for 5 seconds or less, the instrument cluster (IC) defaults the temperature gauge to the last setting, based upon the last known good temperature status message. If the instrument cluster (IC) does not receive the engine coolant temperature status message from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the temperature gauge to cold (C). If the engine coolant temperature data is deemed invalid by the instrument cluster (IC) for 5 seconds or more, the instrument cluster (IC) sets DTC U2199 and defaults the temperature gauge to cold (C).

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative tachometer, speedometer or odometer.

1. DTC U2199 (Invalid Engine Coolant Temperature Data) - sets in continuous memory in the instrument cluster (IC) if the instrument cluster (IC) receives invalid engine coolant temperature data from the PCM for 5 seconds or more.

This pinpoint test is intended to diagnose the following

1. PCM concern
2. Instrument cluster (IC)

The PCM uses the cylinder head temperature (CHT) sensor to measure the engine coolant temperature. The instrument cluster (IC) receives the engine coolant temperature data from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster (IC) monitors the engine coolant temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

The PCM receives the vehicle speed sensor (VSS) data from the output shaft speed (OSS) sensor. The instrument cluster (IC) receives the VSS signal from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster (IC) monitors the VSS input from the PCM and commands the speedometer with a corresponding movement of the pointer.

If the vehicle speed data is missing for 5 seconds or less or if the instrument cluster (IC) receives invalid vehicle speed data for 5 seconds or less, the instrument cluster (IC) defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the instrument cluster (IC) does not receive the vehicle speed data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the speedometer to 0 km/h (0 mph). If the vehicle speed data received is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the speedometer to 0 km/h (0 mph).

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative tachometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following

1. PCM concern
2. Instrument cluster (IC)

The PCM receives the vehicle speed sensor (VSS) data from the output shaft speed (OSS) sensor. The instrument cluster (IC) receives the VSS signal from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster (IC) monitors the VSS input from the PCM and commands the speedometer with a corresponding movement of the pointer. Factors that could potentially affect the accuracy of the speedometer are configurable items such as tire size.

If the vehicle speed data is missing for 5 seconds or less or if the instrument cluster (IC) receives invalid vehicle speed data for 5 seconds or less, the instrument cluster (IC) defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the instrument cluster (IC) does not receive the vehicle speed data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the speedometer to 0 km/h (0 mph). If the vehicle speed data received is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the speedometer to 0 km/h (0 mph).

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative tachometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following

1. PCM
2. Instrument cluster (IC)

The instrument cluster (IC) receives the odometer rolling count data from the PCM over the high speed controller area network (HS-CAN) communication bus. The instrument cluster (IC) monitors the odometer rolling count input from the PCM and commands the odometer with a display in the vacuum fluorescent display area.

If the instrument cluster (IC) does not receive the odometer rolling count data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the odometer display to all dashes (-----). If the odometer rolling count data is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the odometer display to all dashes (-----).

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer, temperature gauge.

1. DTC B2143 (NVM Memory Failure) - is a continuous and on-demand DTC that sets if the instrument cluster (IC) non-volatile memory (NVM) is corrupted. If the instrument cluster (IC) determines the NVM to be corrupt, the instrument cluster (IC) sets DTC B2143 and displays ERROR in the vacuum fluorescent display area.

This pinpoint test is intended to diagnose the following

1. PCM concern
2. Instrument cluster (IC)

The PCM uses the crankshaft position sensor to measure the engine RPM. The PCM sends the instrument cluster (IC) the data over the high speed controller area network (HS-CAN) communication bus, to command the tachometer gauge according to the data.

If the engine RPM data is invalid for 5 seconds or less or if the instrument cluster (IC) does not receive the engine RPM data for 5 seconds or less, the instrument cluster (IC) defaults the tachometer to the last setting, based upon the last known good RPM message. If the instrument cluster (IC) does not receive the engine RPM data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the tachometer to 0 RPM. If the engine RPM data is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2196 and defaults the tachometer to 0 RPM.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following

1. PCM concern
2. Instrument cluster (IC)

The PCM uses the crankshaft position sensor to measure the engine RPM. The PCM sends the instrument cluster (IC) the data over the high speed controller area network (HS-CAN) communication bus, to command the tachometer gauge according to the data.

If the engine RPM data is invalid for 5 seconds or less or if the instrument cluster (IC) does not receive the engine RPM data for 5 seconds or less, the instrument cluster (IC) defaults the tachometer to the last setting, based upon the last known good RPM message. If the instrument cluster (IC) does not receive the engine RPM data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the tachometer to 0 RPM. If the engine RPM data is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2196 and defaults the tachometer to 0 RPM.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, temperature gauge or odometer.

This pinpoint test is intended to diagnose the following

1. PCM concern
2. Instrument cluster (IC)

The engine oil pressure switch is a normally open switch. The instrument cluster (IC) provides a reference voltage to the engine oil pressure switch through circuit CMC24 (GY). When the oil pressure is within normal ranges, the engine oil pressure switch closes to ground, pulling the reference voltage low in the instrument cluster (IC). The instrument cluster (IC) senses the low reference voltage and turns off the low oil pressure warning indicator. When the engine oil pressure is low, the engine oil pressure switch opens, sending the reference voltage to the normal voltage in the instrument cluster (IC). The instrument cluster (IC) senses the normal reference voltage and turns the low oil pressure warning indicator on.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Engine oil pressure switch
3. Base engine oil pressure concern
4. Instrument cluster (IC)

The low fuel indicator illuminates when the distance to empty (DTE) calculation reaches 80 km (50 miles) or less. The DTE is calculated internally by the instrument cluster (IC) from data received from the PCM and the fuel gauge. When the instrument cluster (IC) receives the data and calculates 80 km (50 miles) or less of fuel remaining in the fuel tank, the fuel gauge indicates low fuel and the instrument cluster (IC) turns on the low fuel indicator.

This pinpoint test is intended to diagnose the following

1. Instrument cluster (IC)

The charging system indicator is controlled by the instrument cluster (IC) based upon data received from the PCM over the high speed controller area network (HS-CAN) communication bus.

If the charging system message is missing or invalid for less than 5 seconds, the charging system indicator remains in the last indication mode (on or off). If the charging system message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the charging system warning indicator on. If the charging data received is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the charging system warning indicator on.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following

1. Charging system concern
2. PCM
3. Instrument cluster (IC)

The instrument cluster (IC) uses 3 basic messaged inputs to control the brake warning indicator. The first 2 are the parking brake warning indicator switch and brake fluid level switch. The third is for the electronic brake distribution, controlled by the ABS. The parking brake warning indicator switch and the brake fluid level switch status are sent from the smart junction box (SJB) over the medium speed controller area network (MS-CAN) communication bus. The electronic brake distribution message is sent from the ABS module over the high speed controller area network (HS-CAN) communication bus lines. The parking brake warning indicator switch is hardwired to the SJB through circuit CMC25 (WH/VT). The brake fluid level switch is hardwired to the SJB through signal circuit CMC19 (GY/VT) and return circuit RMC19 (YE/GY).

The SJB provides a reference voltage to both the parking brake warning indicator switch and the brake fluid level switch. When the parking brake is applied, the parking brake warning indicator switch closes to ground through circuit GD133 (BK), providing a ground to the SJB and pulling signal circuit CMC25 (WH/VT) low. When a low brake fluid level condition exists, the low brake fluid level switch closes to ground through circuit GD120 (BK/GN), pulling signal circuit CMC19 (GY/VT) low. The SJB monitors the parking brake and the brake fluid level inputs sending the instrument cluster (IC) a message to turn the brake warning indicator on when the parking brake is applied, when the brake fluid level is low or if the SJB detects an open in the brake fluid level signal or return circuits. When the ABS module detects a base brake system concern or other ABS related concerns that affect the electronic brake distribution function, the ABS module sends a message to the instrument cluster (IC) to illuminate both the ABS warning indicator and the brake warning indicator.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Parking brake warning indicator switch
3. Brake fluid level switch (part of the master cylinder)
4. SJB
5. Instrument cluster (IC)

The instrument cluster (IC) uses 3 basic messaged inputs to control the brake warning indicator. The first 2 are the parking brake warning indicator switch and brake fluid level switch. The third is for the electronic brake distribution, controlled by the ABS. The parking brake warning indicator switch and the brake fluid level switch status are sent from the smart junction box (SJB) over the medium speed controller area network (MS-CAN) communication bus. The electronic brake distribution message is sent from the ABS module over the high speed controller area network (HS-CAN) communication bus lines. The parking brake warning indicator switch is hardwired to the SJB through circuit CMC25 (WH/VT). The brake fluid level switch is hardwired to the SJB through signal circuit CMC19 (GY/VT) and return circuit RMC19 (YE/GY).

The SJB provides a reference voltage to both the parking brake warning indicator switch and the brake fluid level switch. When the parking brake is applied, the parking brake warning indicator switch closes to ground through circuit GD133 (BK), providing a ground to the SJB and pulling signal circuit CMC25 (WH/VT) low. When a low brake fluid level condition exists, the low brake fluid level switch closes to ground through circuit GD120 (BK/GN), pulling signal circuit CMC19 (GY/VT) low. The SJB monitors the parking brake and the brake fluid level inputs sending the instrument cluster (IC) a message to turn the brake warning indicator on when the parking brake is applied, when the brake fluid level is low or if the SJB detects an open in the brake fluid level signal or return circuits. When the ABS module detects a base brake system concern or other ABS related concerns that affect the electronic brake distribution function, the ABS module sends a message to the instrument cluster (IC) to illuminate both the ABS warning indicator and the brake warning indicator.

If the brake fluid level or parking brake status messages are missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0140 and defaults the brake warning indicator on. If the instrument cluster (IC) does not receive the ABS status message or the electronic brake distribution (EBD) message from the ABS module for more than 5 seconds, the instrument cluster (IC) sets DTC U0121 and defaults the ABS warning indicator on. If the brake warning message received from the ABS module is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the brake warning indicator on.

1. DTC B2479 (Park Brake Switch Circuit Short to Ground) - is an on-demand DTC that sets when the SJB detects a short to ground on the parking brake warning indicator switch input, circuit CMC25 (WH/VT) during the module self-test.
2. DTC C1125 (Brake Fluid Level Sensor Input Circuit Failure) - is a continuous and on-demand DTC that sets in the SJB if the SJB detects an open or a short to ground on the brake fluid level input circuit CMC19 (GY/VT).

Note. If DTC U0140 is set in the instrument cluster (IC), other symptoms may also be present such as tire pressure monitoring system (TPMS), instrument panel backlighting, and door ajar indication.

Note. Both the ABS warning indicator and the brake warning indicator illuminate if the input to turn on the brake warning indicator is received from the ABS module.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Parking brake warning indicator switch
3. Brake fluid level switch (part of the master cylinder)
4. ABS concern
5. SJB
6. Instrument cluster (IC)

The ABS module provides the ABS status to the instrument cluster (IC) over the high speed controller area network (HS-CAN) communication bus. If a fault condition exists in the ABS, the ABS module sends the instrument cluster (IC) a command to either flash the ABS warning indicator or to turn it on. If the ABS status message is missing for less than 5 seconds, the ABS warning indicator remains in the last indication mode (on or off). If the ABS status message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0121 and defaults the ABS warning indicator on. If the ABS data received is deemed invalid by the instrument cluster (IC) for 5 seconds or longer, the instrument cluster (IC) sets DTC U2023 and defaults the ABS warning indicator on.

This pinpoint test is intended to diagnose the following

1. ABS module
2. Instrument cluster (IC)

The MIL is controlled by the instrument cluster (IC) using data sent from the PCM over the high speed controller area network (HS-CAN) communication bus. If the MIL status message is missing for less than 5 seconds, the MIL remains in the last indication mode (on or off). If the MIL status message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the MIL on. If the MIL message is deemed invalid for longer than 5 seconds, the instrument cluster (IC) defaults the MIL on.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following

1. PCM
2. Instrument cluster (IC)

The restraints control module (RCM) monitors the safety belt position through the safety belt buckle switch. The RCM provides the safety belt buckle status to the instrument cluster (IC) over the high speed controller area network (HS-CAN) communication bus. If the instrument cluster (IC) does not receive the safety belt buckle switch status from the RCM for greater than 5 seconds, the instrument cluster (IC) sets DTC U0151 and defaults the safety belt warning indicator off. If the RCM message is deemed invalid by the instrument cluster (IC) for greater than 5 seconds, the instrument cluster (IC) sets DTC U2023 and defaults the safety belt warning indicator off.

This pinpoint test is intended to diagnose the following

1. RCM
2. Instrument cluster (IC)

The passive anti-theft system (PATS) indicator proves out for 3 seconds when the key is turned to the ON or START position under normal operation. If there is a PATS concern, the anti-theft indicator either flashes rapidly or glows steadily (for more than 3 seconds) when the key is turned to the ON or the START position. PATS also flashes the anti-theft indicator every 2 seconds at key off to act as a visual theft deterrent. The anti-theft indicator operation is controlled by the instrument cluster (IC).

This pinpoint test is intended to diagnose the following

1. PATS concern
2. Instrument cluster (IC)

The instrument cluster (IC) receives the supplemental restraint system (SRS) status from the restraints control module (RCM) over the high speed controller area network (HS-CAN) communication bus. If a SRS concern is detected, the RCM sets a DTC and sends a message to the instrument cluster (IC) to turn on the air bag warning indicator. If the SRS status message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0151 and defaults the air bag warning indicator on. If the SRS status message is deemed invalid for more than 5 seconds, the instrument cluster (IC) sets DTC U2023 and defaults the air bag warning indicator on.

This pinpoint test is intended to diagnose the following

1. RCM
2. Instrument cluster (IC)

When the multifunction switch is in the LH or RH TURN position or if the high beams are on, a message is sent to the instrument cluster (IC) from the SJB over the medium speed controller area network (CAN) communication bus. The instrument cluster (IC) upon receipt of the LH/RH turn or high beam on message, flashes the LH or RH turn signal indicator on and off or illuminates the high beam indicator.

This pinpoint test is intended to diagnose the following

1. Turn signal concern
2. High beam concern
3. SJB
4. Instrument cluster (IC)

The instrument cluster (IC) receives the traction assist data from the ABS module over the high speed controller area network (HS-CAN) communication bus. The traction assist indicator flashes when the vehicle traction control is in active mode or is being controlled by the ABS module. The traction assist indicator turns on steady if the traction assist system has been disabled through the traction assist switch or if a fault condition exists in the system. The instrument cluster (IC) monitors the traction assist message from the ABS module and either flashes the traction assist indicator or turns it on steady depending on the condition. If the traction control message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0121 in continuous memory and defaults the traction assist indicator on.

This pinpoint test is intended to diagnose the following

1. Traction assist concern
2. ABS module
3. Instrument cluster (IC)

The instrument cluster (IC) receives the speed control signal from the PCM over the high speed controller area network (HS-CAN) communication bus. When the speed control is engaged, the PCM sends a message to the instrument cluster (IC) to illuminate the speed control indicator. If the speed control message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the speed control indicator off.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following

1. PCM
2. Instrument cluster (IC)

The instrument cluster (IC) receives the powertrain malfunction data from the PCM for the electronic throttle control status and the transmission status and from the 4X4 control module for the AWD status over the high speed controller area network (HS-CAN) communication bus. When a fault condition exists in electronic throttle control system or the transmission, the PCM provides the instrument cluster (IC) with a message to turn on the powertrain malfunction (wrench) warning indicator. When a AWD fault condition exists, the 4X4 control module sends the instrument cluster (IC) a message to turn on the powertrain malfunction (wrench) warning indicator.

If the electronic throttle control or transmission message is missing for greater than 5 seconds, the instrument cluster (IC) sets DTC U0100 and defaults the powertrain malfunction (wrench) warning indicator ON.

If the AWD status message is missing for greater than 5 seconds, the instrument cluster (IC) sets DTC U0114 and defaults the powertrain malfunction (wrench) warning indicator ON.

Note. If U0100 is set in the instrument cluster (IC) other symptoms may also be present such as an inoperative speedometer, tachometer or temperature gauge.

This pinpoint test is intended to diagnose the following

1. Electronic throttle control concern
2. Transmission concern
3. AWD concern
4. Instrument cluster (IC)

The PCM monitors the fuel tank evaporative emission system for significant leaks that occur following refueling of the vehicle. Once the PCM detects a fuel vapor leak, the PCM sends the instrument cluster (IC) a message over the communication network to turn on the check fuel cap indicator. DTC P0457 sets in the PCM following a successful cruise test, which is initiated when the vehicle is driven at a steady speed above 64 km/h (40 mph) for a duration of approximately 4-5 minutes. If the PCM is unable to successfully run the cruise test, the instrument cluster (IC) does not receive the check fuel cap message and the check fuel cap indicator remains off.

If the instrument cluster (IC) does not receive the fuel cap off data from the PCM for 5 seconds or less, the instrument cluster (IC) defaults the check fuel cap indicator to the last setting, based upon the last known good data message. If the instrument cluster (IC) does not receive the fuel cap off data from the PCM for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the fuel cap off indicator off.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, temperature gauge (except Hybrid) or odometer.

1. DTC P0457 (Evaporative Emission System Leak Detected) (fuel cap loose/off) - sets in the PCM if a fuel tank pressure change greater than -23.7 kPa (-7 in-Hg) of vacuum within 30 seconds after refueling occurs, or there is an excessive purge (fuel vapor) flow of greater than 454 g (1.0 lb) per minute.

This pinpoint test is intended to diagnose the following

1. PCM
2. Instrument cluster (IC)

The instrument cluster (IC) receives the overdrive (O/D) off signal from the PCM over the high speed controller area network (HS-CAN) communication bus. When the O/D function is selected off, the PCM sends a message to the instrument cluster (IC) to illuminate the O/D off indicator. If the O/D on/off message is missing or if the data is deemed invalid by the instrument cluster (IC) for more than 5 seconds, the instrument cluster (IC) sets DTC U0100 in continuous memory and defaults the O/D off indicator off.

Note. If DTC U0100 is set in the instrument cluster (IC), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following

1. O/D concern
2. PCM
3. Instrument cluster (IC)

The instrument cluster (IC) receives the TPMS messages from the smart junction box (SJB) over the medium speed controller area network (MS-CAN) communication bus. If the SJB determines that the tire pressure has exceeded the low tire pressure limits, a message is sent to the instrument cluster (IC) to turn the TPMS warning indicator on. If a TPMS fault condition exists, the SJB sends a message to the instrument cluster (IC) to flash the TPMS warning indicator. If the TPMS status message is missing for less than 5 seconds, the instrument cluster (IC) defaults the TPMS warning indicator to the last setting (on or off), based upon the last known good message received. If the TPMS status message is missing for more than 5 seconds, the instrument cluster (IC) sets DTC U0140 and flashes the TPMS indicator for approximately 75 seconds then turns on the indicator steady.

Note. If DTC U0140 is set in the SJB, other symptoms may also be present such as high beam indicator, RH/LH turn indicators, instrument panel backlighting, and door ajar indication.

This pinpoint test is intended to diagnose the following

1. TPMS concern
2. SJB
3. Instrument cluster (IC)

The instrument cluster (IC) sets DTC B1318 in continuous memory and on-demand if the instrument cluster (IC) detects low battery voltage on the B+ keep alive voltage input, circuit SBP26 (YE/RD).

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. High circuit resistance
3. Instrument cluster (IC)

With the ignition switch in the START or RUN position, the instrument cluster (IC) receives voltage from the smart junction box (SJB) through circuit CBP29 (WH/VT). With the ignition switch in the OFF position, the instrument cluster (IC) receives its keep-alive voltage from the SJB through circuit SBP26 (YE/RD). The instrument cluster (IC) also monitors the ignition switch position data received from the SJB over the medium speed controller area network (MS-CAN) communication bus.

1. DTC B2A20 (Ignition Stuck in START) - is a continuous memory DTC that sets in the instrument cluster (IC) when the instrument cluster (IC) detects the SJB messaged ignition state in start for greater than 15 seconds.
2. DTC U2472 (Unexpected Ignition State) - is a continuous and on-demand DTC that sets in the instrument cluster (IC) when the cluster detects a discrepancy between the hardwired voltage input and the messaged ignition state inputs from the SJB. The SJB messaged input indicates RUN while the hardwired input indicates RUN/START for more than 5 seconds.

This pinpoint test is intended to diagnose the following

1. Fuse(s)
2. Wiring, terminals or connectors
3. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0100 if data messages received from the PCM over the high speed controller area network (HS-CAN) are missing for greater than 5 seconds. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

Note. Once the instrument cluster (IC) sets DTC U0100, multiple gauges or indicators are likely to be inoperative in the cluster. Other modules that require data from the instrument cluster (IC) all set communication DTCs and may also exhibit system function concerns.

This pinpoint test is intended to diagnose the following

1. PCM
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0114 if data messages received from the 4X4 control module over the high speed controller area network (HS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0121 if data messages received from the ABS module over the high speed controller area network (HS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0140 if data messages received from the smart junction box (SJB) over the high speed controller area network (HS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0151 if data messages received from the RCM over the high speed controller area network (HS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0164 if data messages received from the heating ventilation air conditioning (HVAC) module over the medium speed controller area network (MS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0208 if data messages received from the driver seat module (DSM) over the medium speed controller area network (MS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The instrument cluster (IC) sets DTC U0230 if data messages received from the power liftgate/trunk module (LTM) over the medium speed controller area network (MS-CAN) are missing. For a complete list of all network messages, refer to MODULE COMMUNICATIONS NETWORK article.

This pinpoint test is intended to diagnose the following

1. Module communication
2. Instrument cluster (IC)

The message center functionality is controlled through the message center switch, which is hardwired to the instrument cluster (IC) through input circuit CMC29 (GN/VT) and return circuit RMC27 (WH/BN). There are 3 message center switch buttons with each button operating a switch that uses different resistance values. The instrument cluster (IC) sends out a reference voltage to the message center switch on the input circuit and monitors the voltage drop when a message center switch button is pressed. The voltage drop will vary depending upon the resistance of each button, providing a specific indication to the instrument cluster (IC) which switch is pressed.

1. DTC B1205 (EIC Switch-1 Assembly Circuit Failure) - is a continuous and on-demand DTC that sets in the instrument cluster (IC) when the instrument cluster (IC) detects any of the message center switch buttons stuck closed for more than 120 seconds continuously or during the on-demand self-test.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Message center switch (part of the steering wheel audio control)
3. Instrument cluster (IC)

The compass module receives voltage from the smart junction box (SJB) through circuit CBP31 (BU/OG) and is grounded through circuit GD133 (BK). The compass module communicates vehicle direction to the instrument cluster (IC) to be displayed in the message center. The compass module uses communication data plus circuit VMC31 (YE/GN) and communication data minus circuit VMC30 (BU/GY) to communicate to the instrument cluster (IC).

1. DTC B2097 (Compass Module Failure) - sets in continuous memory and on-demand in the instrument cluster (IC) if the instrument cluster (IC) detects invalid data sent from the compass module during the self-test.
2. DTC U2013 (Compass Module Is Not Responding) - sets in continuous memory in the instrument cluster (IC) if the compass data is invalid from the compass module. The DTC is also set on-demand if the compass module fails to respond during a self-test. If the instrument cluster (IC) fails to receive the compass data, the instrument cluster (IC) sets DTC U2013 and defaults the compass display to (--).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Compass module

The compass sensor module communicates the vehicle direction to the instrument cluster (IC) through the compass communication data plus circuit VMC31 (YE/GN) and compass communication data minus circuit VMC30 (BU/GY). The magnetic fields generated by the earths north and south poles are divided into zones that differ from each other with respect to how the magnetic fields appear. The magnetic north can change by up to 4 degrees between zones and become noticeable across multiple zones. The compass zone must be set to the correct zone for the compass to read accurately. Factors within the vehicle may affect the ability of the compass module to accurately read the magnetic north. Calibrating the compass allows the compass module to compensate for vehicle factors that influence the accuracy of the compass.

Note. Outside factors such as bridges, steel structures, tall buildings and power lines also affect compass accuracy.

This pinpoint test is intended to diagnose the following

1. Zone setting
2. Calibration
3. Compass sensor module

The washer fluid level switch is hardwired to the instrument cluster (IC) through circuit CMC20 (VT) and grounded through circuit GD123 (BK/GY). The instrument cluster (IC) provides a reference voltage to the washer fluid level switch through the signal circuit CMC20 (VT). When the washer fluid level is normal, the washer fluid level switch opens. When the washer fluid is low, the washer fluid level switch closes to ground pulling the signal circuit reference voltage low.

1. DTC B1482 (Wiper Washer Fluid Level Sensor Circuit Short To Ground) - sets on-demand when the instrument cluster (IC) detects a short to ground on the low washer fluid level input, circuit CMC20 (VT). This DTC can only set when running the on-demand self-test.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Washer fluid level switch
3. Instrument cluster (IC)

The instrument cluster (IC) receives the door ajar status for the LH front, RH front, LH rear and RH rear door ajar switch from the smart junction box (SJB) over the medium speed controller area network (MS-CAN) communication bus. When the instrument cluster (IC) receives a message from the SJB that one or more doors are open or ajar, the instrument cluster (IC) turns on the applicable door ajar warning.

Note. If DTC U0140 is set in the SJB, other symptoms may also be present such as high beam indicator, RH/LH turn indicators, instrument panel backlighting and tire pressure monitoring system (TPMS).

This pinpoint test is intended to diagnose the following

1. Interior lighting concern
2. Instrument cluster (IC)

The instrument cluster (IC) receives the key-in-ignition warning status from the smart junction box (SJB) over the medium speed controller area network (MS-CAN). The key-in-ignition warning switch (part of the ignition switch) is hardwired to the SJB through circuit CDC30 (BU/GY). When the key is inserted into the ignition lock cylinder, the key-in-ignition switch closes and supplies voltage to the SJB. The SJB monitors the door ajar input from the LH front door and the key-in-ignition switch status. When the key is inserted into the ignition lock cylinder and the LH front door is open or ajar, the SJB sends the instrument cluster (IC) a chime request message to sound the key-in-ignition warning chime. The headlamps on warning chime sounds when the driver door is opened with the ignition switch in the OFF position, and the headlamp switch is in the PARK or HEADLAMP ON position.

The SJB receives the headlamp switch status from the headlamp switch and the LH front door ajar status from the LH front door ajar switch through hardwired circuitry. The SJB communicates the headlamp on chime request to the instrument cluster (IC) when the headlamps or parking lamps are on and the driver door is opened. The autolamps feature must not be selected for the headlamps on warning chime to operate.

1. DTC B1352 (Ignition Key-In Circuit Failure) - is an on-demand DTC that sets if the SJB detects an open on the key-in-ignition switch input, circuit CDC30 (BU/GY) or if the SJB detects ignition START, RUN/START or RUN/ACC inputs without the key-in-ignition input.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Key-in-ignition warning switch (part of the ignition switch)
3. SJB

The instrument cluster (IC) receives the key-in-ignition warning status from the smart junction box (SJB) over the medium speed controller area network (MS-CAN). The key-in-ignition warning switch (part of the ignition switch) is hardwired to the SJB through circuit CDC30 (BU/GY). When the key is inserted into the ignition lock cylinder, the key-in-ignition switch closes and supplies voltage to the SJB. The SJB monitors the door ajar input from the LH front door and the key-in-ignition switch status. When the key is inserted into the ignition lock cylinder and the driver door is open or ajar, the SJB sends the instrument cluster (IC) a chime request message to sound the key-in-ignition warning chime.

1. DTC B1352 (Ignition Key-In Circuit Failure) - is an on-demand DTC that sets if the SJB detects an open on the key-in-ignition switch input, circuit CDC30 (BU/GY) or if the SJB detects ignition START, RUN/START or RUN/ACC inputs without the key-in-ignition input.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Key-in-ignition switch (part of the ignition switch)
3. SJB
4. Instrument cluster (IC)

The smart junction box (SJB) receives the headlamp switch status from the headlamp switch and the LH front door ajar status from the LH front door ajar switch through hardwired circuitry. The headlamps on warning chime sounds when the LH front door is opened with the ignition switch in the OFF position, and the headlamp switch is in the PARK or HEADLAMP ON position. The SJB communicates the headlamp on chime request to the instrument cluster (IC) when the headlamps or parking lamps are on and the driver door is opened. The autolamps feature must not be selected for the headlamps on warning chime to operate.

This pinpoint test is intended to diagnose the following

1. Door ajar indication
2. SJB
3. Instrument cluster (IC)

The instrument cluster (IC) receives the safety belt and Belt-Minder® requests from the restraints control module (RCM) over the high speed controller area network (HS-CAN). The safety belt warning chime sounds for approximately 6 seconds when the driver safety belt is not fastened and the ignition lock cylinder is turned from the OFF/LOCK or ACC to the ON or START position.

The Belt-Minder® feature supplements the safety belt warning function and is enabled after the safety belt warning is complete. The Belt-Minder® simultaneously sounds the chime and illuminates the safety belt warning lamp in the instrument cluster (IC) once the vehicle speed has exceeded 5 km/h (3 mph), and remains active for 5 minutes from the time it is started.

Note. Make sure that the safety belt/Belt-Minder® chime operation is verified with the vehicle moving at least 5 km/h (3 mph).

This pinpoint test is intended to diagnose the following

1. Safety belt warning indication concern
2. Speedometer concern
3. Instrument cluster (IC)

The instrument cluster (IC) receives the command to turn on the parking brake warning chime from the smart junction box (SJB) over the medium speed controller area network (MS-CAN). The SJB uses vehicle speed data and parking brake switch status to determine when to send the command to turn on the parking brake warning chime.

The parking brake warning chime sounds if the ignition switch is in the ON position, the parking brake is engaged, and the vehicle speed is greater than 5 km/h (3 mph). The parking brake warning chime stops sounding and resets if the parking brake is released, the ignition switch is not in the ON position, if the vehicle speed is below 5 km/h (3 mph), or after 90 seconds from the time the chime is activated.

Note. Make sure that the brake warning chime operation is verified with the vehicle moving at least 5 km/h (3 mph) with the parking brake slightly applied (just enough to turn the brake warning indicator on).

This pinpoint test is intended to diagnose the following

1. Brake warning indication
2. Instrument cluster (IC)

See also:
• SUPPLEMENTAL RESTRAINT SYSTEM
• AUTOMATIC TRANSAXLE/TRANSMISSION - 6F50